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Abstract:

The disclosure pertains to amphiphilic block copolymers comprising an
aliphatic polycarbonate chain coupled to a hydrophilic polymer. Such
amphiphilic polymers may have the formula A-L-B, where A- is a
polycarbonate or polyethercarbonate chain having from about 3 to about
500 repeating units, L is a linker moiety and --B is a hydrophilic
oligomer having from about 4 to about 200 repeating units. Provided
copolymers are useful as surfactants capable of emulsifying aqueous
solutions and supercritical carbon dioxide. Provided copolymers also have
utility as additives for use in enhanced oil recovery methods.

Claims:

1. A polymer composition comprising a block copolymer having a formula:
##STR00107## where X is selected from the group consisting of: halogen;
--OH; azide, nitrile, and --ORz; each Ra, Rb, Rc, and
Rd is independently selected from the group consisting of: hydrogen,
halogen, --CH2ORz, optionally substituted C1-10 aliphatic,
optionally substituted 6- to 14-membered aromatic, optionally substituted
3- to 14-membered heterocyclic, and optionally substituted 5- to
14-membered heteroaryl, and where any two or more of Ra, Rb,
Rc, and Rd may be taken together to form an optionally
substituted 3- to 12-membered ring, optionally containing one or more
heteroatoms; L is a bond or a polyfunctional moiety; B is a hydrophilic
oligomer having from about 4 to about 100 repeating units; n is an
integer between 4 and 100; Rz is selected from the group consisting
of R10, --C(O)R10, --SO2R10, --Si(R10)3,
--C(O)N(R10)2; and R10 is an optionally substituted moiety
selected from the group consisting of: C1-20 aliphatic; C1-12
heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered
heteroaryl.

2. The polymer composition of claim 1, wherein the block copolymer has
the formula: ##STR00108## wherein, R100 is optionally present, and
if present is selected from the group consisting of --CH3,
--CF3, --CH2CH3, --CH2ORz, and --CH2Cl.

3. The polymer composition of claim 2, wherein R100 is absent.

4. The polymer composition of claim 2, wherein R100 is present.

5. The polymer composition of claim 4, wherein the block copolymer has
the formula: ##STR00109##

6. The polymer composition of claim 4, wherein the block copolymer has
the formula: ##STR00110## wherein X' is selected from the group
consisting of --OH and --ORz.

7. The polymer composition of claim 4, wherein R100 is a methyl
group.

8. The polymer composition of claim 4, wherein R100 is an ethyl
group.

9. The polymer composition of claim 4, wherein R100 is a random
mixture of methyl groups and one or more moieties selected from group
consisting of ethyl, trifluoromethyl, chloromethyl, --CH2ORz
and a C6-30 alkyl group.

15. The polymer composition of claim 14, wherein the block copolymer has
the formula: ##STR00111## wherein, m is an integer between 5 and 200;
--Z-- is an optionally substituted C1-6 aliphatic group; and --Y is
selected from the group consisting of --H and Rz.

22. The polymer composition of claim 15, wherein the copolymer has the
formula ##STR00112##

23. The polymer composition of claim 22, wherein X is not --OH.

24. The polymer composition of claim 15, wherein the copolymer has the
formula: ##STR00113## wherein X', is --OH or --ORz, and Y' is
selected from the group consisting of optionally substituted C1-8
aliphatic, a silyl protecting group, and --C(O)R.sup.10.

44. The polymer composition of claim 18, wherein the block copolymer
comprises polyoxymethylene and a terpolymer of two or more epoxides and
carbon dioxide.

45. The polymer composition of claim 44, wherein the terpolymer of two or
more epoxides and carbon dioxide comprises poly(butylene-co-propylene
carbonate).

46. The polymer composition of claim 44, wherein the terpolymer of two or
more epoxides and carbon dioxide comprises a terpolymer of propylene
oxide, a C6-30 alkyl epoxide and carbon dioxide.

47. A polymer composition comprising a block copolymer having a formula:
##STR00117## wherein X' is selected from the group consisting of --OH
and --ORz; R100 is optionally present, and if present is
selected from the group consisting of --CH3, --CF3,
--CH2CH3, --CH2ORz, and --CH2Cl; each n is
independently an integer between 4 and 100; --Z-- is an optionally
substituted C1-6 aliphatic group; m is an integer between 5 and 200;
Rz is selected from the group consisting of R10,
--C(O)R10, --SO2R10, --Si(R10)3,
--C(O)N(R10)2; and R10 is at each occurrence an optionally
substituted moiety independently selected from the group consisting of:
C1-12 aliphatic; C1-12 heteroaliphatic; 6- to 14-membered aryl;
and 5- to 14-membered heteroaryl.

48. The polymer composition of claim 47, wherein R100 is absent.

49. The polymer composition of claim 47, wherein R100 is present.

50. The polymer composition of claim 49, wherein R100 is a methyl
group.

51. The polymer composition of claim 49, wherein R100 is an ethyl
group.

52. The polymer composition claim 49, wherein R100 is a random
mixture of methyl groups and one or more moieties selected from group
consisting of ethyl, trifluoromethyl, chloromethyl, --CH2ORz.

58. The polymer composition of claim 2, wherein the copolymer is selected
from the group consisting of: ##STR00118##

59. The polymer composition of claim 47, wherein the copolymer is
selected from the group consisting of: ##STR00119##

60. The polymer composition of any one of claims 1-59, wherein on average
in the composition n is between 4 and 100.

61. The polymer composition of any one of claims 1-59, wherein on average
in the composition n is between 4 and 20.

62. The polymer composition of any one of claims 1-59, wherein on average
in the composition n is between 4 and 200.

63. The polymer composition of any one of claims 1-59, wherein on average
in the composition n is between 4 and 100.

64. The polymer composition of any one of claims 1-59, wherein on average
in the composition n is between 8 and 20.

65. The polymer composition of any one of claims 1-59, wherein on average
in the composition n is between 4 and 50.

66. The polymer composition of any one of claims 1-59, wherein on average
in the composition n is between 4 and 20.

67. The polymer composition of any one of claims 1-59, wherein the
polycarbonate chain contains greater than about 90% carbonate linkages.

68. The polymer composition of any one of claims 1-59, wherein the
polycarbonate chain contains greater than about 95% carbonate linkages.

69. The polymer composition of any one of claims 1-59, wherein the
polycarbonate chain contains essentially no detectable ether linkages.

70. The polymer composition of any one of claim 4-9, 15-25, 27, 47 or
49-57, wherein, on average in the composition, the head-to-tail ratio of
adjacent ##STR00120## groups is greater than 80%.

71. The polymer composition of claim 70, wherein the head-to-tail ratio
is greater than 90%.

72. The polymer composition of claim 71, wherein the head-to-tail ratio
is greater than 95%.

73. The polymer composition of any one of claims 1-59, wherein the
copolymer has an average molecular weight between 500 and 5,000 g/mol.

74. The polymer composition of claim 55, wherein the copolymer has an
average molecular weight between 500 and 2,500 g/mol.

75. The polymer composition of claim 55, wherein the copolymer has an
average molecular weight between 800 and 2,000 g/mol.

76. The polymer composition of any one of claims 1-59, wherein the
copolymer has a solubility in supercritical CO2 of at least 0.05
weight % at a pressure of 4,000 psi or higher.

77. The polymer composition of claim 76, wherein the copolymer has a
solubility in supercritical CO2 of at least 0.1 weight % at a
pressure of 3,000 psi or higher.

78. The polymer composition of claim 76, wherein the copolymer has a
solubility in supercritical CO2 of at least 0.2 weight % at a
pressure of 3,000 psi or higher.

79. The polymer composition of claim 76, wherein the copolymer has a
solubility in supercritical CO2 of at least 0.5 weight % at a
pressure of 3,000 psi or higher.

80. The polymer composition of claim 76, wherein the copolymer has a
solubility in supercritical CO2 of about 1.0 weight % at a pressure
of 1,000 psi or higher.

81. A method of forming an emulsion of supercritical CO2 and an
aqueous phase, the method comprising a step of agitating supercritical
CO2 and the aqueous phase in the presence of a block copolymer
having a formula: ##STR00121## wherein X is selected from the group
consisting of halogen; --OH; azide, nitrile, and --ORz; each
Ra, Rb, Rc, and Rd is independently selected from the
group consisting of: hydrogen, halogen, --CH2ORz, optionally
substituted C1-10 aliphatic, optionally substituted 6- to
14-membered aromatic, optionally substituted 3- to 14-membered
heterocyclic, and optionally substituted 5- to 14-membered heteroaryl,
and where any two or more of Ra, Rb, Rc, and Rd may
be taken together to form an optionally substituted 3- to 12-membered
ring, optionally containing one or more heteroatoms; L is a bond or a
polyfunctional moiety; B is a hydrophilic oligomer having from about 4 to
about 100 repeating units; n is an integer between 4 and 100; Rz is
selected from the group consisting of R10, --C(O)R10,
--SO2R10, --Si(R10)3, --C(O)N(R10)2; and
R10 is an optionally substituted moiety selected from the group
consisting of: C1-20 aliphatic; C1-12 heteroaliphatic; 6- to
14-membered aryl; and 5- to 14-membered heteroaryl.

82. The method of claim 81, wherein the block co-polymer has the formula
##STR00122## wherein R100 is optionally present, and if present is
selected from the group consisting of --CH3, --CF3,
--CH2CH3, --CH2ORz, --CH2Cl, and a C6-30
alkyl group.

83. A method of modifying the viscosity of a fluid comprising a mixture
of supercritical CO2 and water, the method comprising a step of
agitating the mixture in the presence of a block copolymer having a
formula: ##STR00123## wherein X is selected from the group consisting
of: halogen, --OH, azide, nitrile, and --ORz; each Ra, Rb,
Rc, and Rd is independently selected from the group consisting
of: hydrogen, halogen, --CH2ORz, optionally substituted
C1-10 aliphatic, optionally substituted 6- to 14-membered aromatic,
optionally substituted 3- to 14-membered heterocyclic, and optionally
substituted 5- to 14-membered heteroaryl, and where any two or more of
Ra, Rb, Rc, and Rd may be taken together to form an
optionally substituted 3- to 12-membered ring, optionally containing one
or more heteroatoms; L is a bond, or a polyfunctional moiety; B is a
hydrophilic oligomer having from about 4 to about 100 repeating units; n
is an integer between 4 and 100; Rz is selected from the group
consisting of R10, --C(O)R10, --SO2R10,
--Si(R10)3, --C(O)N(R10)2; and R10 is an
optionally substituted moiety selected from the group consisting of:
C1-20 aliphatic; C1-12 heteroaliphatic; 6- to 14-membered aryl;
and 5- to 14-membered heteroaryl.

84. The method of claim 83, wherein the block co-polymer has the formula
##STR00124## wherein R100 is optionally present, and if present is
selected from the group consisting of --CH3, --CF3,
--CH2CH3, --CH2ORz, --CH2Cl, and a C6-30
alkyl group.

85. A method of forming an emulsion of supercritical CO2 and an
aqueous phase, the method comprising a step of agitating supercritical
CO2 and the aqueous phase in the presence of a block copolymer
having a formula: ##STR00125## wherein X' is selected from the group
consisting of --OH and --ORz; R100 is optionally present, and
if present is selected from the group consisting of --CH3,
--CF3, --CH2CH3, --CH2ORz, and --CH2Cl;
each n is independently an integer between 4 and 100; --Z-- is an
optionally substituted C1-6 aliphatic group; m is an integer between
5 and 200; Rz is selected from the group consisting of R10,
--C(O)R10, --SO2R10, --Si(R10)3,
--C(O)N(R10)2; and R10 is at each occurrence an optionally
substituted moiety independently selected from the group consisting of:
C1-12 aliphatic; C1-12 heteroaliphatic; 6- to 14-membered aryl;
and 5- to 14-membered heteroaryl.

86. The method of claim 84 or 85, wherein the copolymer is provided as a
solution in supercritical CO.sub.2.

87. A method of modifying the viscosity of a fluid comprising a mixture
of supercritical CO2 and water, the method comprising a step of
agitating the mixture in the presence of a block copolymer having a
formula: ##STR00126## wherein X' is selected from the group consisting
of --OH and --ORz; R100 is optionally present, and if present
is selected from the group consisting of --CH3, --CF3,
--CH2CH3, --CH2ORz, and --CH2Cl; each n is
independently an integer between 4 and 100; --Z-- is an optionally
substituted C1-6 aliphatic group; m is an integer between 5 and 200;
Rz is selected from the group consisting of R10,
--C(O)R10, --SO2R10, --Si(R10)3,
--C(O)N(R10)2; and R10 is at each occurrence an optionally
substituted moiety independently selected from the group consisting of:
C1-12 aliphatic; C1-12 heteroaliphatic; 6- to 14-membered aryl;
and 5- to 14-membered heteroaryl.

88. The method of claim 87, wherein the copolymer is provided as a
solution in supercritical CO.sub.2.

89. The method of claim 88, further comprising the step of pumping the
copolymer solution into an oil well.

90. The polymer composition of any one of claims 1-59, wherein the
copolymer forms a polymersome.

91. The method of any one of claim 81, 83, 85, or 87-89, wherein the
copolymer forms a polymersome.

[0002] Carbon dioxide is of great interest as a solvent in chemical
processing because it is non-flammable, relatively non-toxic, and
naturally abundant. These "green" properties have prompted the
development of a host of new applications for CO2, some of which
were made possible by the discovery of functional groups that enable
miscibility of various moieties with CO2 at moderate pressures.
Development of CO2 surfactants, for example, allows for processes
such as emulsion polymerization or dry cleaning with CO2.

[0003] CO2 has been extensively employed to recover oil from
underground formations, as it is inexpensive, non-flammable, relatively
non-toxic and remediation is not required. In enhanced oil recovery
(EOR), a flooding agent is pumped into the oil-bearing formation to move
the petroleum to exit wells (see for example U.S. Pat. Nos. 4,480,696,
4,921,635 and 5,566,470). Water is most often used as the flooding agent,
yet intimate contact between petroleum and water creates
cross-contamination that mandates remediation of large volumes of
organic-contaminated water. Indeed, a life cycle analysis of polystyrene
performed during the 1980's suggested that the extraction of petroleum
from the ground produces more liquid waste than any other process step
over the entire cradle-to-grave lifespan of the material. Carbon dioxide
would be a more sustainable flooding agent than water, but the viscosity
of CO2 is too low to efficiently recover petroleum from the
formation. Rather than sweep the oil before it, carbon dioxide "fingers"
its way through the petroleum and hence leaves most of the oil behind.

[0004] Researchers in the petroleum engineering field have tried for
decades to design additives that can raise the viscosity of carbon
dioxide (at low concentration) to levels that would render
CO2-flooding more practical, but success has been elusive. Additives
have been synthesized that enhanced the viscosity of simple hydrocarbons,
yet which were not soluble in CO2 without the use of impractically
high fractions of co-solvent. Other additives have been identified that
were CO2-soluble but which did produce any changes in the viscosity
of CO2.

[0005] Polymer-based surfactants have also been developed for use in
increasing the viscosity of CO2 and/or CO2 solubility (WO
00/35998 and U.S. Pat. No. 6,686,438). However, these materials have not
found much practical utility due to issues with their relative solubility
in CO2 and water, specifically in their tendency to be hydrophilic
but not very CO2-philic.

[0006] Improvement in the efficiency of CO2-flooding will promote the
use of CO2 over water in EOR and thus reduce the volume of liquid
waste produced during petroleum extraction. Use of CO2 in EOR also
results in its sequestration in rock formations, potentially an important
part of an overall CO2 sequestration strategy. Thus, what is at
first glance simply a technical problem in petroleum engineering has
significant environmental ramifications as well. This discussion
highlights the need for compositions that increase the viscosity of
fluids comprising supercritical CO2 and water.

SUMMARY OF THE INVENTION

[0007] The present disclosure provides, among other things, amphiphilic
polymers having the formula A-L-B, wherein each of A, L, and B is as
defined and described in classes and subclasses herein.

[0008] In some embodiments, the present disclosure provides amphiphilic
polymers having the formula A-B-A, wherein each of A and B is as defined
and described in classes and subclasses herein.

[0009] In some embodiments, the present disclosure provides methods to
make polymers of formula A-L-B or A-B-A.

[0011] Definitions of specific functional groups and chemical terms are
described in more detail below. For purposes of this invention, the
chemical elements are identified in accordance with the Periodic Table of
the Elements, CAS version, Handbook of Chemistry and Physics, 75th
Ed., inside cover, and specific functional groups are generally defined
as described therein. Additionally, general principles of organic
chemistry, as well as specific functional moieties and reactivity, are
described in Organic Chemistry, Thomas Sorrell, University Science Books,
Sausalito, 1999; Smith and March March's Advanced Organic Chemistry,
5th Edition, John Wiley & Sons, Inc., New York, 2001; Larock,
Comprehensive Organic Transformations, VCH Publishers, Inc., New York,
1989; Carruthers, Some Modern Methods of Organic Synthesis, 3rd
Edition, Cambridge University Press, Cambridge, 1987; the entire contents
of each of which are incorporated herein by reference.

[0012] Certain compounds of the present invention can comprise one or more
asymmetric centers, and thus can exist in various stereoisomeric forms,
e.g., enantiomers and/or diastereomers. Thus, inventive compounds and
compositions thereof may be in the form of an individual enantiomer,
diastereomer or geometric isomer, or may be in the form of a mixture of
stereoisomers. In certain embodiments, the compounds of the invention are
enantiopure compounds. In certain embodiments, mixtures of enantiomers or
diastereomers are provided.

[0013] Furthermore, certain compounds, as described herein may have one or
more double bonds that can exist as either the Z or E isomer, unless
otherwise indicated. The invention additionally encompasses the compounds
as individual isomers substantially free of other isomers and
alternatively, as mixtures of various isomers, e.g., racemic mixtures of
enantiomers.

[0014] As used herein, the term "isomers" includes any and all geometric
isomers and stereoisomers. For example, "isomers" include cis- and
trans-isomers, E- and Z-isomers, R- and S-enantiomers, diastereomers,
(D)-isomers, (L)-isomers, racemic mixtures thereof, and other mixtures
thereof, as falling within the scope of the invention. For instance, an
stereoisomer may, in some embodiments, be provided substantially free of
one or more corresponding stereoisomers, and may also be referred to as
"stereochemically enriched."

[0015] Where a particular enantiomer is preferred, it may, in some
embodiments be provided substantially free of the opposite enantiomer,
and may also be referred to as "optically enriched." "Optically
enriched," as used herein, means that the compound is made up of a
significantly greater proportion of one enantiomer. In certain
embodiments the compound is made up of at least about 90% by weight of a
preferred enantiomer. In other embodiments the compound is made up of at
least about 95%, 98%, or 99% by weight of a preferred enantiomer.
Preferred enantiomers may be isolated from racemic mixtures by any method
known to those skilled in the art, including chiral high pressure liquid
chromatography (HPLC) and the formation and crystallization of chiral
salts or prepared by asymmetric syntheses. See, for example, Jacques, et
al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New
York, 1981); Wilen, S. H., et al., Tetrahedron 33:2725 (1977); Eliel, E.
L. Stereochemistry of Carbon Compounds (McGraw-Hill, NY, 1962); Wilen, S.
H. Tables of Resolving Agents and Optical Resolutions p. 268 (E. L.
Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, Ind. 1972).

[0017] The term "aliphatic" or "aliphatic group", as used herein, denotes
a hydrocarbon moiety that may be straight-chain (i.e., unbranched),
branched, or cyclic (including fused, bridging, and spirofused
polycyclic) and may be completely saturated or may contain one or more
units of unsaturation, but which is not aromatic. Unless otherwise
specified, aliphatic groups contain 1-30 carbon atoms. In certain
embodiments, aliphatic groups contain 1-12 carbon atoms. In certain
embodiments, aliphatic groups contain 1-8 carbon atoms. In certain
embodiments, aliphatic groups contain 1-6 carbon atoms. In some
embodiments, aliphatic groups contain 1-5 carbon atoms. In some
embodiments, aliphatic groups contain 1-4 carbon atoms. In some
embodiments, aliphatic groups contain 1-3 carbon atoms. In some
embodiments, aliphatic groups contain 1-2 carbon atoms. Suitable
aliphatic groups include, but are not limited to, linear or branched,
alkyl, alkenyl, and alkynyl groups, and hybrids thereof such as
(cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

[0018] The term "unsaturated", as used herein, means that a moiety has one
or more double or triple bonds.

[0019] The terms "cycloaliphatic", "carbocycle", or "carbocyclic", used
alone or as part of a larger moiety, refer to a saturated or partially
unsaturated cyclic aliphatic monocyclic or bicyclic ring systems, as
described herein, having from 3 to 12 members, wherein the aliphatic ring
system is optionally substituted as defined above and described herein.
Cycloaliphatic groups include, without limitation, cyclopropyl,
cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl,
cycloheptyl, cycloheptenyl, cyclooctyl, cyclooctenyl, and
cyclooctadienyl. In some embodiments, the cycloalkyl has 3-6 carbons. The
terms "cycloaliphatic", "carbocycle" or "carbocyclic" also include
aliphatic rings that are fused to one or more aromatic or nonaromatic
rings, such as decahydronaphthyl or tetrahydronaphthyl, where the radical
or point of attachment is on the aliphatic ring. In certain embodiments,
the term "3- to 8-membered carbocycle" refers to a 3- to 8-membered
saturated or partially unsaturated monocyclic carbocyclic ring. In
certain embodiments, the terms "3- to 14-membered carbocycle" and
"C3-14 carbocycle" refer to a 3- to 8-membered saturated or
partially unsaturated monocyclic carbocyclic ring, or a 7- to 14-membered
saturated or partially unsaturated polycyclic carbocyclic ring. In
certain embodiments, the term "C3-20 carbocycle" refers to a 3- to
8-membered saturated or partially unsaturated monocyclic carbocyclic
ring, or a 7- to 20-membered saturated or partially unsaturated
polycyclic carbocyclic ring.

[0023] The term "aryl" used alone or as part of a larger moiety as in
"aralkyl", "aralkoxy", or "aryloxyalkyl", refers to monocyclic and
polycyclic ring systems having a total of five to 20 ring members,
wherein at least one ring in the system is aromatic and wherein each ring
in the system contains three to twelve ring members. The term "aryl" may
be used interchangeably with the term "aryl ring". In certain embodiments
of the present invention, "aryl" refers to an aromatic ring system which
includes, but is not limited to, phenyl, biphenyl, naphthyl, anthracyl
and the like, which may bear one or more substituents. Also included
within the scope of the term "aryl", as it is used herein, is a group in
which an aromatic ring is fused to one or more additional rings, such as
benzofuranyl, indanyl, phthalimidyl, naphthimidyl, phenantriidinyl, or
tetrahydronaphthyl, and the like. In certain embodiments, the terms "6-
to 10-membered aryl" and "C6-10 aryl" refer to a phenyl or an 8- to
10-membered polycyclic aryl ring. In certain embodiments, the term "6- to
14-membered aryl" refers to a phenyl or an 8- to 14-membered polycyclic
aryl ring.

[0024] The terms "heteroaryl" and "heteroar-", used alone or as part of a
larger moiety, e.g., "heteroaralkyl", or "heteroaralkoxy", refer to
groups having 5 to 14 ring atoms, preferably 5, 6, or 9 ring atoms;
having 6, 10, or 14 π electrons shared in a cyclic array; and having,
in addition to carbon atoms, from one to five heteroatoms. The term
"heteroatom" refers to nitrogen, oxygen, or sulfur, and includes any
oxidized form of nitrogen or sulfur, and any quaternized form of a basic
nitrogen. Heteroaryl groups include, without limitation, thienyl,
furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl,
oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl,
pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl, purinyl,
naphthyridinyl, benzofuranyl and pteridinyl. The terms "heteroaryl" and
"heteroar-", as used herein, also include groups in which a
heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or
heterocyclyl rings, where the radical or point of attachment is on the
heteroaromatic ring. Nonlimiting examples include indolyl, isoindolyl,
benzothienyl, benzofuranyl, dibenzofuranyl, indazolyl, benzimidazolyl,
benzthiazolyl, quinolyl, isoquinolyl, cinnolinyl, phthalazinyl,
quinazolinyl, quinoxalinyl, 4H-quinolizinyl, carbazolyl, acridinyl,
phenazinyl, phenothiazinyl, phenoxazinyl, tetrahydroquinolinyl,
tetrahydroisoquinolinyl, and pyrido[2,3-b]-1,4-oxazin-3(4H)-one. A
heteroaryl group may be mono- or bicyclic. The term "heteroaryl" may be
used interchangeably with the terms "heteroaryl ring", "heteroaryl
group", or "heteroaromatic", any of which terms include rings that are
optionally substituted. The term "heteroaralkyl" refers to an alkyl group
substituted by a heteroaryl, wherein the alkyl and heteroaryl portions
independently are optionally substituted. In certain embodiments, the
term "5- to 10-membered heteroaryl" refers to a 5- to 6-membered
heteroaryl ring having 1 to 3 heteroatoms independently selected from
nitrogen, oxygen, or sulfur, or an 8- to 10-membered bicyclic heteroaryl
ring having 1 to 4 heteroatoms independently selected from nitrogen,
oxygen, or sulfur. In certain embodiments, the term "5- to 14-membered
heteroaryl" refers to a 5- to 6-membered heteroaryl ring having 1 to 3
heteroatoms independently selected from nitrogen, oxygen, or sulfur, or
an 8- to 14-membered polycyclic heteroaryl ring having 1 to 4 heteroatoms
independently selected from nitrogen, oxygen, or sulfur.

[0025] As used herein, the terms "heterocycle", "heterocyclyl",
"heterocyclic radical", and "heterocyclic ring" are used interchangeably
and refer to a stable 5- to 7-membered monocyclic or 7- to 14-membered
bicyclic heterocyclic moiety that is either saturated or partially
unsaturated, and having, in addition to carbon atoms, one or more,
preferably one to four, heteroatoms, as defined above. When used in
reference to a ring atom of a heterocycle, the term "nitrogen" includes a
substituted nitrogen. As an example, in a saturated or partially
unsaturated ring having 0-3 heteroatoms selected from oxygen, sulfur or
nitrogen, the nitrogen may be N (as in 3,4-dihydro-2H-pyrrolyl), NH (as
in pyrrolidinyl), or +NR (as in N-substituted pyrrolidinyl). In some
embodiments, the term "3- to 7-membered heterocyclic" refers to a 3- to
7-membered saturated or partially unsaturated monocyclic heterocyclic
ring having 1 to 2 heteroatoms independently selected from nitrogen,
oxygen, or sulfur. In some embodiments, the term "3- to 8-membered
heterocycle" refers to a 3- to 8-membered saturated or partially
unsaturated monocyclic heterocyclic ring having 1 to 2 heteroatoms
independently selected from nitrogen, oxygen, or sulfur. In some
embodiments, the term "3- to 12-membered heterocyclic" refers to a 3- to
8-membered saturated or partially unsaturated monocyclic heterocyclic
ring having 1 to 2 heteroatoms independently selected from nitrogen,
oxygen, or sulfur, or a 7- to 12-membered saturated or partially
unsaturated polycyclic heterocyclic ring having 1-3 heteroatoms
independently selected from nitrogen, oxygen, or sulfur. In some
embodiments, the term "3- to 14-membered heterocycle" refers to a 3- to
8-membered saturated or partially unsaturated monocyclic heterocyclic
ring having 1 to 2 heteroatoms independently selected from nitrogen,
oxygen, or sulfur, or a 7- to 14-membered saturated or partially
unsaturated polycyclic heterocyclic ring having 1-3 heteroatoms
independently selected from nitrogen, oxygen, or sulfur.

[0026] A heterocyclic ring can be attached to its pendant group at any
heteroatom or carbon atom that results in a stable structure and any of
the ring atoms can be optionally substituted. Examples of such saturated
or partially unsaturated heterocyclic radicals include, without
limitation, tetrahydrofuranyl, tetrahydrothienyl, pyrrolidinyl,
pyrrolidonyl, piperidinyl, pyrrolinyl, tetrahydroquinolinyl,
tetrahydroisoquinolinyl, decahydroquinolinyl, oxazolidinyl, piperazinyl,
dioxanyl, dioxolanyl, diazepinyl, oxazepinyl, thiazepinyl, morpholinyl,
and quinuclidinyl. The terms "heterocycle", "heterocyclyl", "heterocyclyl
ring", "heterocyclic group", "heterocyclic moiety", and "heterocyclic
radical", are used interchangeably herein, and also include groups in
which a heterocyclyl ring is fused to one or more aryl, heteroaryl, or
cycloaliphatic rings, such as indolinyl, 3H-indolyl, chromanyl,
phenanthridinyl, or tetrahydroquinolinyl, where the radical or point of
attachment is on the heterocyclyl ring. A heterocyclyl group may be mono-
or bicyclic. The term "heterocyclylalkyl" refers to an alkyl group
substituted by a heterocyclyl, wherein the alkyl and heterocyclyl
portions independently are optionally substituted.

[0027] As used herein, the term "partially unsaturated" refers to a ring
moiety that includes at least one double or triple bond. The term
"partially unsaturated" is intended to encompass rings having multiple
sites of unsaturation, but is not intended to include aryl or heteroaryl
moieties, as herein defined.

[0029] As described herein, compounds of the invention may contain
"optionally substituted" moieties. In general, the term "substituted",
whether preceded by the term "optionally" or not, means that one or more
hydrogens of the designated moiety are replaced with a suitable
substituent. Unless otherwise indicated, an "optionally substituted"
group may have a suitable substituent at each substitutable position of
the group, and when more than one position in any given structure may be
substituted with more than one substituent selected from a specified
group, the substituent may be either the same or different at every
position. Combinations of substituents envisioned by this invention are
preferably those that result in the formation of stable or chemically
feasible compounds. The term "stable", as used herein, refers to
compounds that are not substantially altered when subjected to conditions
to allow for their production, detection, and, in certain embodiments,
their recovery, purification, and use for one or more of the purposes
disclosed herein.

[0031] Suitable monovalent substituents on R.sup.∘ (or the
ring formed by taking two independent occurrences of R.sup.∘
together with their intervening atoms), are independently halogen,
--(CH2)0-2R.sup.•, -(haloR.sup.•),
--(CH2)0-2OH, --(CH2)0-2OR.sup.•,
--(CH2)0-2CH(OR.sup.•)2; --O(haloR.sup.•),
--CN, --N3, --(CH2)0-2C(O)R.sup.•,
--(CH2)0-2C(O)OH, --(CH2)0-2C(O)OR.sup.•,
--(CH2)0-4C(O)N(R.sup.∘)2;
--(CH2)0-2SR.sup.•, --(CH2)0-2SH,
--(CH2)0-2NH2, --(CH2)0-2NHR.sup.•,
--(CH2)0-2NR.sup.•2, --NO2,
--SiR.sup.•3, --OSiR.sup.•3, --C(O)SR.sup.•,
--(C1-4 straight or branched alkylene)C(O)OR.sup.•, or
--SSR.sup.• wherein each R.sup.• is unsubstituted or where
preceded by "halo" is substituted only with one or more halogens, and is
independently selected from C1-4 aliphatic, --CH2Ph,
--O(CH2)0-1Ph, or a 5- to 6-membered saturated, partially
unsaturated, or aryl ring having 0-4 heteroatoms independently selected
from nitrogen, oxygen, or sulfur. Suitable divalent substituents on a
saturated carbon atom of R.sup.∘ include ═O and ═S.

[0032] Suitable divalent substituents on a saturated carbon atom of an
"optionally substituted" group include the following: ═O, ═S,
═NNR*2, ═NNHC(O)R*, ═NNHC(O)OR*, ═NNHS(O)2R*,
═NR*, ═NOR*, --O(C(R*2))2-3O--, or
--S(C(R*2))2-3S--, wherein each independent occurrence of R* is
selected from hydrogen, C1-6 aliphatic which may be substituted as
defined below, or an unsubstituted 5-6-membered saturated, partially
unsaturated, or aryl ring having 0-4 heteroatoms independently selected
from nitrogen, oxygen, or sulfur. Suitable divalent substituents that are
bound to vicinal substitutable carbons of an "optionally substituted"
group include: --O(CR*2)2-3O--, wherein each independent
occurrence of R* is selected from hydrogen, C1 aliphatic which may
be substituted as defined below, or an unsubstituted 5- to 6-membered
saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms
independently selected from nitrogen, oxygen, or sulfur.

[0033] Suitable substituents on the aliphatic group of R* include halogen,
--R.sup.•, -(haloR.sup.•), --OH, --OR.sup.•,
--O(haloR.sup.•), --CN, --C(O)OH, --C(O)OR.sup.•, --NH2,
--NHR.sup.•, --NR.sup.•2, or --NO2, wherein each
R.sup.• is unsubstituted or where preceded by "halo" is substituted
only with one or more halogens, and is independently C1-4 aliphatic,
--CH2Ph, --O(CH2)0-1Ph, or a 5- to 6-membered saturated,
partially unsaturated, or aryl ring having 0-4 heteroatoms independently
selected from nitrogen, oxygen, or sulfur.

[0034] Suitable substituents on a substitutable nitrogen of an "optionally
substituted" group include --R.sup.†, --NR.sup.†2,
--C(O)R.sup.†, --C(O)OR.sup.†, --C(O)C(O)R.sup.†,
--C(O)CH2C(O)R.sup.†, --S(O)2R.sup.†,
--S(O)2NR.sup.†2, --C(S)NR.sup.†2,
--C(NH)NR.sup.†2, or
--N(R.sup.†)S(O)2R.sup.†; wherein each R.sup.†
is independently hydrogen, C1-6 aliphatic which may be substituted
as defined below, unsubstituted --OPh, or an unsubstituted 5- to
6-membered saturated, partially unsaturated, or aryl ring having 0-4
heteroatoms independently selected from nitrogen, oxygen, or sulfur, or,
notwithstanding the definition above, two independent occurrences of
R.sup.†, taken together with their intervening atom(s) form an
unsubstituted 3- to 12-membered saturated, partially unsaturated, or aryl
mono- or bicyclic ring having 0-4 heteroatoms independently selected from
nitrogen, oxygen, or sulfur.

[0035] Suitable substituents on the aliphatic group of R.sup.† are
independently halogen, --R.sup.•, -(haloR.sup.•), --OH,
--OR.sup.•, --O(haloR.sup.•), --CN, --C(O)OH,
--C(O)OR.sup.•, --NH2, --NHR.sup.•,
--NR.sup.•2, or --NO2, wherein each R.sup.• is
unsubstituted or where preceded by "halo" is substituted only with one or
more halogens, and is independently C1 aliphatic, --CH2Ph,
--O(CH2)0-1Ph, or a 5- to 6-membered saturated, partially
unsaturated, or aryl ring having 0-4 heteroatoms independently selected
from nitrogen, oxygen, or sulfur.

[0036] In some chemical structures herein, substituents are shown attached
to a bond which crosses another bond of a depicted molecule. This means
that one or more of the substituents may be attached to the molecule at
any available position (usually in place of a hydrogen atom of the parent
structure). In cases where an atom of a molecule so substituted has two
substitutable positions, two groups may be present on the same ring atom.
When more than one substituent is present, each is defined independently
of the others, and each may have a different structure. In cases where
the substituent shown crossing a bond of the molecule is --R, this has
the same meaning as if the ring were said to be "optionally substituted"
as described in the preceding paragraphs.

[0037] As used herein, the terms "head-to-tail" or "HT", refer to the
regiochemistry of adjacent repeating units in a polymer chain. For
example, in the context of poly(propylene carbonate), the term
head-to-tail based on the three regiochemical possibilities depicted
below:

##STR00001##

The term head-to-tail ratio (H:T) refers to the proportion of
head-to-tail linkages to the sum of all other regiochemical
possibilities.

[0038] As used herein, the term "mixture," when applied to a substituent,
means that the substituent varies throughout the molecule and not all
occurrences are the same (i.e., it refers to a plurality of the
substituent rather than a single occurrence of the substituent). For
example, "R1 is a mixture of methyl, ethyl, and propyl groups" will
be understood to mean "R1 is selected from the group consisting of
methyl, ethyl, and propyl, wherein not all occurrences of R1 are the
same."

[0040] FIG. 2 depicts supercritical CO2 solubility of a composition
of the present invention comprising a diblock copolymer of PPC and PEG.

[0041] FIG. 3 depicts supercritical CO2 solubility of a composition
of the present invention comprising a diblock copolymer of PPC and PEG.

[0042]FIG. 4 depicts supercritical CO2 solubility of a composition
of the present invention comprising a triblock copolymer of PPC and PEG.

[0043] FIG. 5 shows the stability over time of CO2/water foams
stabilized by PPC/PEG diblock co-polymers (28-34A) and PPC/PEG/PPC
triblock copolymers (28-53B-53C and -53D) of the present invention where
the bottom half of the y-axis represents the depth of foam in the aqueous
phase, and the upper half of the y-axis represents the height of foam in
the supercritical CO2 phase.

[0044] FIG. 6 shows the stability over time of CO2/water foams
stabilized by PPC/PPG/PPC triblock copolymers of the present invention
where each block in the copolymer comprises between 3 and 12 repeat
units.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0045] The present disclosure encompasses the recognition that block
copolymers comprising a polycarbonate chain have utility in a number of
applications involving interaction with CO2. In some embodiments,
the present disclosure provides copolymers and compositions thereof
comprising a polycarbonate or a polyether-polycarbonate chain, methods of
making, and methods of using the same.

[0046] In certain embodiments, provided block copolymers of formula A-L-B,
where A- is a polycarbonate or a polyether-polycarbonate chain having
from about 3 to about 500 repeating units, L is a linker moiety or a
covalent bond and --B is a hydrophilic oligomer having from about 4 to
about 500 repeating units.

[0047] In some embodiments, A- is a polycarbonate chain. In some
embodiments, A- is a polycarbonate chain containing greater than about
95%, greater than about 98%, or greater than about 99% carbonate
linkages. In some embodiments, A- is an aliphatic polycarbonate chain. In
certain embodiments, the aliphatic polycarbonate is a copolymer of an
optionally substituted epoxide and carbon dioxide. In certain
embodiments, the polycarbonate is selected from the group consisting of
poly(ethylene carbonate), poly(propylene carbonate), poly(butylene
carbonate), poly(glycidylether carbonate), poly(chloromethylethylene
carbonate), poly(cyclopentene carbonate), poly(cyclohexene carbonate),
poly(3-vinyl cyclohexene carbonate) and random-, block- or
tapered-copolymers of any two or more of the above.

[0048] In certain embodiments, a polycarbonate chain A- is poly(propylene
carbonate). In certain embodiments, a polycarbonate chain A- is
poly(ethylene carbonate). In certain embodiments, a polycarbonate chain
A- is poly(chloromethylethylene carbonate). In certain embodiments, a
polycarbonate chain A- is poly(butylene carbonate). In certain
embodiments, a polycarbonate chain A- is a poly(glycidyl ether
carbonate). In certain embodiments, a polycarbonate chain A- is a
poly(glycidyl ester carbonate). In certain embodiments, a polycarbonate
chain A- is a random copolymer comprising poly(propylene carbonate) and
poly(ethylene carbonate). In some embodiments, a polycarbonate chain A-
is a random copolymer comprising poly(propylene carbonate) and
poly(n-butylene carbonate). In certain embodiments, a polycarbonate chain
A- is a random copolymer comprising poly(propylene carbonate) and a
polycarbonate derived from the epoxide of a C6-30 alpha olefin.

[0049] In certain embodiments, a polycarbonate chain A- includes about 3
to about 500 repeating units. In certain embodiments, a polycarbonate
chain includes about 5 to about 50 repeating units. In certain
embodiments, a polycarbonate chain includes about 3 to about 20 repeating
units. In certain embodiments, a polycarbonate chain includes about 10 to
about 15 repeating units. In certain embodiments, a polycarbonate chain
includes about 20 to about 50 repeating units.

[0050] In some embodiments, a polymer chain A- is a random or tapered
polyether polycarbonate copolymer. In certain embodiments, the proportion
of ether linkages in a polyether polycarbonate chain A- ranges from about
0.1% to about 50%. In certain embodiments, the proportion of ether
linkages in a polyether polycarbonate chain A-ranges from about 0.1% to
about 44%. In certain embodiments, the proportion of ether linkages in a
polyether polycarbonate chain A- ranges from about 0.1% to about 43%. In
certain embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 42%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 41%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 40%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 35%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 30%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 25%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 20%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 15%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 10%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 5%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- ranges from about 0.1% to about 2%.

[0051] In certain embodiments, the proportion of ether linkages in a
polyether polycarbonate chain A- is less than 50%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- is less than 44%. In certain embodiments, the
proportion of ether linkages in a polyether polycarbonate chain A- is
less than 43%. In certain embodiments, the proportion of ether linkages
in a polyether polycarbonate chain A- is less than 42%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- is less than 41%. In certain embodiments, the
proportion of ether linkages in a polyether polycarbonate chain A- is
less than 40%. In certain embodiments, the proportion of ether linkages
in a polyether polycarbonate chain A- is less than 35%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- is less than 30%. In certain embodiments, the
proportion of ether linkages in a polyether polycarbonate chain A- is
less than 25%. In certain embodiments, the proportion of ether linkages
in a polyether polycarbonate chain A- is less than 20%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- is less than 15%. In certain embodiments, the
proportion of ether linkages in a polyether polycarbonate chain A- is
less than 10%. In certain embodiments, the proportion of ether linkages
in a polyether polycarbonate chain A- is less than 9%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- is less than 8%. In certain embodiments, the
proportion of ether linkages in a polyether polycarbonate chain A- is
less than 7%. In certain embodiments, the proportion of ether linkages in
a polyether polycarbonate chain A- is less than 6%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- is less than 5%. In certain embodiments, the
proportion of ether linkages in a polyether polycarbonate chain A- is
less than 4%. In certain embodiments, the proportion of ether linkages in
a polyether polycarbonate chain A- is less than 3%. In certain
embodiments, the proportion of ether linkages in a polyether
polycarbonate chain A- is less than 2%. In certain embodiments, the
proportion of ether linkages in a polyether polycarbonate chain A- is
less than 1%.

[0052] In certain embodiments, the proportion of ether linkages in a
polyether polycarbonate chain A- ranges from about 0.1% to about 25%. In
certain embodiments the proportion of ether linkages in a polyether
polycarbonate chain A- is less than about 10%. In certain embodiments the
proportion of ether linkages in a polyether polycarbonate chain A- ranges
from about 1% to about 5%. In certain embodiments, the proportion of
ether linkages in a polyether polycarbonate chain A- ranges from about
20% to about 50%.

[0053] In certain embodiments, L is a covalent bond (i.e. A- is bonded
directly to --B). In other embodiments, L is a polyfunctional moiety
having appropriate functionality to form a covalent chemical bond with
both the polycarbonate chain and the hydrophilic oligomer. In certain
instances, L is a moiety formed by the reaction of one functional group
on A- and one functional group on --B with a polyfunctional molecule
capable of reaction with the functional groups on A- and --B thereby
linking them. Examples of suitable polyfunctional moieties for L include,
but are not limited to: agents that can form one or more linkages such as
ester, amide, ether, amine, thioether, carbonate, or other similar
linkages. Examples of polyfunctional molecules suitable for incorporation
as L include, but are not limited to: phosgene, diacids, anhydrides,
acrylates, diisocyanates, epoxides, diols, diamines, hydroxy mercaptans,
mercapto acids, hydroxy acids, amino acids, and any precursors or
reactive equivalents thereof.

[0054] In certain embodiments, a linker L is a moiety formed directly by
the reaction of complementary functional groups on termini of A- and --B.
Examples of such moieties include, but are not limited to: L being an
ester, (formed from an alcohol group on the terminus of A- and a carboxy
group on the terminus of --B, or vice versa); L being an amide; (formed
from an amine group on the terminus of A- and a carboxy group on the
terminus of --B, or vice versa); L being an olefin (formed, for example,
by olefin metathesis); L being a heterocycle, (for example a triazole
formed by cycloaddition of an azide and an alkyne), and L being a
cyclohexene ring formed by Diels Alder cycloaddition of a diene and a
dienophile.

[0055] In certain embodiments, a hydrophilic oligomer --B is a polyether
chain. In some embodiments, --B is a polyolefin chain bearing hydrophilic
functional groups. In certain embodiments, a hydrophilic oligomer --B is
a polyamine chain. In certain embodiments, --B is selected from the group
consisting of polyoxymethylene, poly(ethylene oxide), poly(propylene
oxide), polyvinyl alcohol, poly(vinyl acetate), partially hydrolyzed
poly(vinyl acetate), poly(acrylic acid), polyacrylamide,
polyethyleneimine, poly(2-hydroxyethyl methacrylate),
poly(N-vinylpyrrolidone), polypeptides, polysaccharides,
polyepoxysuccinic acid, poly(methyl vinyl ether), poly(allylamine),
poly(2-ethyl-2-oxazoline), and block, tapered or random copolymers of any
two or more of the above. In some embodiments, --B is polyoxymethylene.
In some embodiments, --B is poly(ethylene oxide). In some embodiments,
--B is poly(propylene oxide).

[0056] In certain embodiments, a hydrophilic oligomer --B includes from
about 4 to about 400 repeating units. In certain embodiments, a
hydrophilic oligomer chain includes less than about 100 repeating units.
In certain embodiments, a hydrophilic oligomer chain includes about 10 to
about 50 repeating units. In certain embodiments, a hydrophilic oligomer
chain includes about 10 to about 20 repeating units.

[0057] In certain embodiments, polymers of the present invention have a
total average molecular weight between about 300 g/mol and about 25,000
g/mol. In certain embodiments, polymers have a total average molecular
weight between about 500 g/mol and about 5,000 g/mol. In some
embodiments, polymers have a total average molecular weight between about
800 g/mol and about 2,500 g/mol.

Polycarbonates

[0058] In certain embodiments, a polymer A-L-B has the formula I:

##STR00002##

where X is selected from the group consisting of: halogen; --OH; azide,
nitrile, and --ORz; [0059] each Ra, Rb, Rc, and
Rd is independently selected from the group consisting of: hydrogen,
halogen, --CH2ORz, optionally substituted C1-30 aliphatic,
optionally substituted 6- to 14-membered aromatic, optionally substituted
3- to 14-membered heterocyclic, and optionally substituted 5- to
14-membered heteroaryl, where any two or more of Ra, Rb,
Rc, and Rd may be taken together to form an optionally
substituted 3- to 12-membered ring, optionally containing one or more
heteroatoms; [0060] L is a bond or a polyfunctional moiety; [0061] B is a
hydrophilic oligomer having from 4 to 100 repeating units; [0062] n is an
integer between 3 and 100; [0063] Rz is selected from the group
consisting of R10, --C(O)R10, --SO2R10,
--Si(R10)3, and --C(O)N(R10)2; and R10 is an
optionally substituted moiety selected from the group consisting of:
C1-20 aliphatic; C1-12 heteroaliphatic; 6- to 14-membered aryl;
and 5- to 14-membered heteroaryl.

[0064] In certain embodiments, polymers of formula I comprise a
polycarbonate chain containing greater than about 90% carbonate linkages.
In certain embodiments, the polycarbonate chain contains greater than
about 95%, greater than about 98%, or greater than about 99% carbonate
linkages. In certain embodiments, the polycarbonate chain contains
essentially no detectable ether linkages.

[0065] In certain embodiments, the polymer A-L-B has the formula I-a:

##STR00003##

where [0066] X, L, B, and n are as defined above, and [0067] R100 is
optionally present, and if present is selected from the group consisting
of CH3, --CF3, --CH2CH3, --CH2ORz,
--CH2Cl, a C3-30 alkyl group, and mixtures of two or more of
these where Rz is as defined above.

[0068] In certain embodiments, a polymer A-L-B has the formula I-b:

##STR00004##

where [0069] X, L, B, R100, and n are as defined above.

[0070] In certain embodiments, a polymer A-L-B has formula I-c:

##STR00005##

where L, B, R100, and n are as defined above, and X' is selected
from the group consisting of --OH and --ORz.

[0071] In certain embodiments, where a polymer has one of the formulae I-b
or I-c, where R100 is present, the head to tail ratio of adjacent

##STR00006##

groups is greater than about 80%. In certain embodiments, the head to
tail ratio is greater than about 90%. In certain embodiments, the head to
tail ratio is greater than about 91%. In certain embodiments, the head to
tail ratio is greater than about 92%. In certain embodiments, the head to
tail ratio is greater than about 93%. In certain embodiments, the head to
tail ratio is greater than about 94%. In certain embodiments, the head to
tail ratio is greater than about 95%.

[0072] In certain embodiments, in polymers of formulae I-a through I-c
R100 is absent (e.g. the polycarbonate chain comprises poly(ethylene
carbonate). In certain embodiments, in polymers of formulae I-a through
I-c, R100 is a methyl group. In certain embodiments, in polymers of
formulae I-a through I-c, R100 is a C3-30 alkyl group. In
certain embodiments, in polymers of formulae I-a through I-c, R100
is a C3-10 alkyl group. In certain embodiments, in polymers of
formulae I-a through I-c, R100 is a C3-6 alkyl group. In
certain embodiments, in polymers of formulae I-a through I-c, R100
is an ethyl group. In certain embodiments, in polymers of formulae I-a
through I-c, R100 is a chloromethyl group. In certain embodiments,
in polymers of formulae I-a through I-c, R100 is a random mixture of
methyl and ethyl groups. In certain embodiments, in polymers of formulae
I-a through I-c, R100 is a random mixture of methyl and chloromethyl
groups. In certain embodiments, in polymers of formulae I-a through I-c,
R100 is a random mixture of methyl and one or more C3-30 alkyl
groups.

[0073] In certain embodiments, in polymers of formulae I-a through I-c,
R100 is a --CH2ORz group. In certain embodiments, the
CH2ORz group comprises an ether group (e.g. the polycarbonate
chain is a poly(glycidyl ether carbonate)). In other embodiments the
CH2ORz group comprises an ester group (e.g. the polycarbonate
chain is a poly(glycidyl ester carbonate)). In certain embodiments,
R100 is a random mixture of C3-30 alkyl and --CH2ORz
groups.

[0074] In certain embodiments, for polymers of formula I-b, X is
--OR10. In other embodiments, for polymers of formula I-b, X is
--OC(O)R10. In certain embodiments, for polymers of formula I-b, X
is Cl, or Br. In certain embodiments, for polymers of formula I-b, X is
azide or a nitrile. In certain embodiments, for polymers of formula I-b,
X is acetate. In certain embodiments, for polymers of formula I-b, X is
trifluoroacetate. In certain embodiments, for polymers of formula I-b, X
is optionally substituted benzoate. In certain embodiments, for polymers
of formulae I-b, X is optionally substituted phenoxide. In certain
embodiments, for polymers of formulae I-b, X is a nitro phenoxide.

[0075] In certain embodiments, for polymers of formulae I-c, X' is --OH.
In certain embodiments, for polymers of formulae I-c, X' is --ORy,
where Ry is an --OH protecting group. In certain embodiments, for
polymers of formulae I-c, X' is --OC(O)R10. In certain embodiments,
for polymers of formulae I-c, X' is --OS(O)2R10. In certain
embodiments, for polymers of formulae I-c, X' is --OSi(R10)3.
In certain embodiments, for polymers of formulae I-c, X' is
--OC(O)N(R10)2. In certain embodiments, for polymers of
formulae I-c, X' is acetate. In certain embodiments, for polymers of
formulae I-c, X' is trifluoroacetate. In certain embodiments, for
polymers of formulae I-c, X' is optionally substituted benzyl or
benzoate.

[0076] The present invention encompasses polymer compositions comprising
polymer chains of formulae I through I-c above wherein the value of n is,
on average, between about 5 and about 200. In certain embodiments, the
value of n is, on average between about 5 and about 100. In certain
embodiments, the value of n is, on average between about 5 and about 50.
In certain embodiments, the value of n is, on average between about 5 and
about 25. In certain embodiments, the value of n is, on average between
about 5 and about 10. In certain embodiments, the value of n is, on
average between about 10 and about 20.

[0077] In certain embodiments, a polymer A-L-B has the formula II:

##STR00007## [0078] where A and L are as defined above, [0079] m is an
integer between about 4 and about 500, [0080] --Z-- is an optionally
substituted C1-6 aliphatic group, and [0081] --Y is selected from
the group consisting of --H and Rz.

[0089] In certain embodiments, for polymers of formulae II through II-d, Z
is --CH2-- (e.g. the hydrophilic oligomer --B is polyoxymethylene).
In certain embodiments, for polymers of formulae II through II-d, Z is
--CH2CH2-- (e.g. the hydrophilic oligomer --B is polyethylene
glycol). In certain embodiments, for polymers of formulae II through
II-d, Z is --CH(CH3)CH2-- (e.g. the hydrophilic oligomer --B is
polypropylene glycol).

[0090] In certain embodiments, in polymers of formulae II, II-a, or II-b,
--Y is an optionally substituted C1-20 aliphatic group. In certain
embodiments, Y is selected from the group consisting of methyl, ethyl,
n-propyl, i-propyl, n-butyl, sec-butyl, t-butyl, allyl and benzyl. In
certain embodiments, in polymers of formulae II, II-a or II-b, --Y is an
acyl group. In certain embodiments, Y is selected from the group
consisting of formate, acetate, trifluoroacetate, propionate, butyrate,
acrylate, and optionally substituted benzoate. In certain embodiments, in
polymers of formulae II, II-a or II-b, --Y is --Si(R10)3. In
certain embodiments, in polymers of formulae II, II-a or II-b, --Y is a
silyl protecting group. In certain embodiments, Y is selected from the
group consisting of trimethylsilyl, triethylsilyl, triisopropyl silyl,
t-butyldimethylsilyl, and t-butyldiphenylsilyl. In certain embodiments,
in polymers of formulae II, II-a or II-b, --Y is --H.

[0091] In certain embodiments, in polymers of formulae II-b through II-d,
R100 is absent (e.g. the polycarbonate chain comprises poly(ethylene
carbonate). In certain embodiments, in polymers of formulae II-b through
II-d, R100 is a C3-30 alkyl group. In certain embodiments, in
polymers of formulae II-b through II-d, R100 is a C3-10 alkyl
group. In certain embodiments, in polymers of formulae II-b through II-d,
R100 is a C3-6 alkyl group. In certain embodiments, in polymers
of formulae II-b through II-d, R100 is a methyl group. In certain
embodiments, in polymers of formulae II-b through II-d, R100 is an
ethyl group. In certain embodiments, in polymers of formulae II-b through
II-d, R100 is a random mixture of methyl and ethyl groups. In
certain embodiments, in polymers of formulae II-b through II-d, R100
is a chloromethyl group. In certain embodiments, in polymers of formulae
II-b through II-d, R100 is a random mixture of methyl and
chloromethyl groups. In certain embodiments, in polymers of formulae II-b
through II-d, R100 is a random mixture of methyl and one or more
C3-30 alkyl groups. In certain embodiments, R100 is partially
absent, wherein one or more n-bracketed repeating units comprise no
R100 group, while the remaining n-bracketing repeating units
comprise a R100 group.

[0092] In certain embodiments, in polymers of formulae II-b through II-d,
R100 is a --CH2ORz group. In certain embodiments, the
CH2ORz group comprises an ether group (e.g. the polycarbonate
chain is a poly(glycidyl ether carbonate)). In other embodiments the
CH2ORz group comprises an ester group (e.g. the polycarbonate
chain is a poly(glycidyl ester carbonate)). In certain embodiments,
R100 is a random mixture of methyl and --CH2ORz groups.

[0093] In certain embodiments, the present invention encompasses polymer
compositions comprising polymer chains of formulae II through II-d above
wherein the value of n is, on average, between about 5 and about 200. In
certain embodiments, the value of n is, on average between about 5 and
about 100. In certain embodiments, the value of n is, on average between
about 5 and about 50. In certain embodiments, the value of n is, on
average between about 5 and about 25. In certain embodiments, the value
of n is, on average between about 10 and about 20. In certain
embodiments, the value of n is, on average between about 5 and about 10.

[0094] In certain embodiments, the present invention encompasses polymer
compositions comprising polymer chains of formulae II through II-d above
wherein the value of m is, on average, between about 4 and about 500. In
certain embodiments, the value of m is, on average between about 5 and
about 200. In certain embodiments, the value of m is, on average between
about 5 and about 50. In certain embodiments, the value of m is, on
average between about 5 and about 25. In certain embodiments, the value
of m is, on average between about 10 and about 20. In certain
embodiments, the value of n is, on average between about 5 and about 10.

[0095] In certain embodiments, where the polymer has one of the formulae
II-c or II-d, and R100 is present, the head to tail ratio of
adjacent

##STR00012##

groups is greater than about 80%. In certain embodiments, the head to
tail ratio is greater than about 90%. In certain embodiments, the head to
tail ratio is greater than about 91%. In certain embodiments, the head to
tail ratio is greater than about 92%. In certain embodiments, the head to
tail ratio is greater than about 93%. In certain embodiments, the head to
tail ratio is greater than about 94%. In certain embodiments, the head to
tail ratio is greater than about 95%.

[0096] In certain embodiments, copolymers of formula A-L-B described above
are characterized in that they have narrow polydispersity indices. In
some embodiments, the PDIs of block copolymers of the present invention
are less than about 2. In certain embodiments, the PDI is less than 1.5.
In some embodiments, the PDI is less than 1.4, less than 1.2 or less than
about 1.1.

[0097] In certain embodiments, a polymer A-L-B is a block copolymer of
polypropylene carbonate) (PPC) or a derivative thereof and poly(ethylene
glycol) (PEG) or a derivative thereof. In certain embodiments, such
PPC-PEG block copolymers have a formula selected from the group
consisting of:

##STR00013## ##STR00014##

[0098] In certain embodiments, a polymer A-L-B is a block copolymer of
poly(propylene carbonate) (PPC) or a derivative thereof and
poly(propylene glycol) (PPG) or a derivative thereof. In certain
embodiments, such PPC-PPG block copolymers have a formula selected from
the group consisting of:

##STR00015## ##STR00016##

[0099] In certain embodiments, a polymer A-L-B is a block copolymer of
poly(propylene carbonate) (PPC) or a derivative thereof and
polyoxymethylene (POM) or a derivative thereof. In certain embodiments,
such PPC-POM block copolymers have a formula selected from the group
consisting of:

##STR00017## ##STR00018##

[0100] In certain embodiments, a polymer A-L-B is a block copolymer of
poly(ethylene carbonate) (PEC) or a derivative thereof and poly(ethylene
glycol) (PEG) or a derivative thereof. In certain embodiments, such
PEC-PEG block copolymers have a formula selected from the group
consisting of:

##STR00019##

[0101] In certain embodiments, a polymer A-L-B is a block copolymer of
poly(ethylene carbonate) (PEC) or a derivative thereof and polypropylene
glycol (PPG) or a derivative thereof. In certain embodiments, such
PEC-PPG block copolymers have a formula selected from the group
consisting of:

##STR00020##

[0102] In certain embodiments, a polymer A-L-B is a block copolymer of
poly(ethylene carbonate) (PEC) or a derivative thereof and
polyoxymethylene (POM) or a derivative thereof. In certain embodiments,
such PEC-POM block copolymers have a formula selected from the group
consisting of:

##STR00021##

[0103] In certain embodiments, a polymer A-L-B is a block copolymer of an
aliphatic polycarbonate (APC) and a polyether, wherein the APC comprises
a random copolymer such as those derived from copolymerization of two or
more different epoxides and carbon dioxide. In certain embodiments, such
block copolymers comprise PEG (poly(ethylene glycol)), polypropylene
glycol), or polyoxymethylene.

[0104] In certain embodiments, APC-PEG block copolymers have a formula
selected from the group consisting of:

##STR00022## ##STR00023##

R1 is a mixture of two or more moieties selected from the group
consisting of --H, methyl, ethyl, C3-30 alkyl, CH2Cl, CF3,
and CH2ORz.

[0105] In certain embodiments, R1 is a mixture of methyl and ethyl
groups. In some embodiments, R1 is a mixture of --H and methyl
groups. In certain embodiments, R1 is a mixture of methyl groups and
C3-6 alkyl groups. In certain embodiments, R1 is a mixture of
methyl groups and C6-24 alkyl groups.

[0106] In certain embodiments, a polymer A-L-B is a block copolymer of an
aliphatic polycarbonate (APC) and poly(propylene glycol) (PPG) or a
derivative thereof, wherein the APC comprises a random copolymer such as
those derived from copolymerization of two or more different epoxides and
carbon dioxide. In certain embodiments, such APC-PPG block copolymers
have a formula selected from the group consisting of:

##STR00024## ##STR00025## [0107] R1 is a mixture of two or more
moieties selected from the group consisting of --H, methyl, ethyl,
C3-30 alkyl, CH2Cl, CF3, and CH2ORz. In certain
embodiments, R1 is a mixture of methyl and ethyl groups. In other
embodiments, R1 is a mixture of --H and methyl groups. In certain
embodiments, R1 is a mixture of methyl groups and C3-6 alkyl
groups. In certain embodiments, R1 is a mixture of methyl groups and
C6-24 alkyl groups.

[0108] In certain embodiments, polymers of the present invention encompass
triblock copolymers having a hydrophilic central block flanked by two
polycarbonate chains. In certain embodiments, such triblock copolymers
have the formula A-B-A, where each A is a polycarbonate or
polyethercarbonate chain having from about 3 to about 500 repeating units
and --B--is a hydrophilic oligomer having from about 4 to about 200
repeating units.

##STR00031## [0120] where Rz, R100, n, n', and m are as
defined above.

[0121] In certain embodiments, in polymers of formulae X-a or X-e, Rz
is R10. In certain embodiments, in polymers of formulae X-a or X-e,
Rz is an optionally substituted aliphatic group. In certain
embodiments, Rz is selected from the group consisting of methyl,
ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, t-butyl, allyl and benzyl.
In certain embodiments, in polymers of formulae X-a or X-e, Rz is an
acyl group. In certain embodiments, Rz is selected from the group
consisting of formate, acetate, trifluoroacetate, propionate, and
optionally substituted benzoate. In certain embodiments, in polymers of
formulae X-a or X-e, Rz is --Si(R10)3. In certain
embodiments, in polymers of formulae X-a or X-e, Rz is a silyl
group. In certain embodiments, Rz is selected from the group
consisting of trimethylsilyl, triethylsilyl, triisopropyl silyl,
t-butyldimethylsilyl, and t-butyldiphenylsilyl. In certain embodiments,
in polymers of formulae X-a or X-e, Rz is a sulfonate group.

[0122] In certain embodiments, in polymers of formulae X-b through X-e,
R100 is absent (e.g. the polycarbonate chain comprises poly(ethylene
carbonate). In certain embodiments, in polymers of formulae X-b through
X-e, R100 is a methyl group. In certain embodiments, in polymers of
formulae X-b through X-e, R100 is an ethyl group. In certain
embodiments, in polymers of formulae X-b through X-e, R100 is a
random mixture of methyl and ethyl groups. In certain embodiments, in
polymers of formulae X-b through X-e, R100 is a chloromethyl group.
In certain embodiments, in polymers of formulae X-b through X-e,
R100 is a random mixture of methyl and chloromethyl groups. In
certain embodiments, in polymers of formulae X-b through X-e, R100
is a random mixture of methyl and one or more C3-30 alkyl groups.

[0123] In certain embodiments, in polymers of formulae X-b through X-e,
R100 is a --CH2ORz group. In certain embodiments, the
CH2ORz group comprises an ether group (e.g. the polycarbonate
chain is a poly(glycidyl ether carbonate)). In some embodiments, the
CH2ORz group comprises an ester group (e.g. the polycarbonate
chain is a poly(glycidyl ester carbonate)). In certain embodiments,
R100 is a random mixture of --H and --CH2ORz groups. In
certain embodiments, R100 is a random mixture of C1-4 alkyl
groups and --CH2ORz groups. In certain embodiments, R100
is a random mixture of methyl and --CH2ORz groups.

[0124] In certain embodiments, provided polymer compositions comprise
polymer chains of formulae X through X-e, wherein the value of n is, on
average, between about 3 and about 200. In certain embodiments, the value
of n is, on average between about 3 and about 100. In certain
embodiments, the value of n is, on average between about 3 and about 50.
In certain embodiments, the value of n is, on average between about 3 and
about 25. In certain embodiments, the value of n is, on average between
about 10 and about 20. In certain embodiments, the value of n is, on
average between about 3 and about 10.

[0125] In certain embodiments, provided polymer compositions comprise
polymer chains of formulae X through X-e above wherein the value of m is,
on average, between about 4 and about 500. In certain embodiments, the
value of m is, on average between about 5 and about 200. In certain
embodiments, the value of m is, on average between about 5 and about 50
In certain embodiments, the value of m is, on average between about 5 and
about 25. In certain embodiments, the value of m is, on average between
about 10 and about 20. In certain embodiments, the value of n is, on
average between about 5 and about 10.

[0126] In certain embodiments, where a provided polymer has one of the
formulae X-b through X-e, the head to tail ratio of adjacent

##STR00032##

groups is greater than about 80%. In certain embodiments, the head to
tail ratio is greater than about 90%. In certain embodiments, the head to
tail ratio is greater than about 92%. In certain embodiments, the head to
tail ratio is greater than about 95%.

[0127] In certain embodiments, provided A-B-A copolymers have narrow
polydisperisity indices. In some embodiments, the PDI of block copolymers
of the present invention is less than about 2. In certain embodiments,
the PDI is less than 1.5. In some embodiments, the PDI is less than 1.4,
less than 1.2 or less than about 1.1.

[0128] In certain embodiments, triblock copolymers of the present
invention comprise copolymers of poly(ethylene glycol) (PEG) or a
derivative thereof and polypropylene carbonate) (PPC) or derivatives
thereof. In certain embodiments, these copolymers have a formula selected
from the group consisting of:

##STR00033##

[0129] In certain embodiments, provided triblock copolymers comprise
copolymers of poly(ethylene glycol) (PEG) or a derivative thereof and
poly(ethylene carbonate) (PEC) or derivatives thereof. In certain
embodiments, these PEG-PEC triblock copolymers have a formula selected
from the group consisting of:

##STR00034##

[0130] In certain embodiments, provided triblock copolymers comprise
copolymers of an aliphatic polycarbonate (APC) and poly(ethylene glycol)
(PEG) or a derivative thereof, wherein an APC comprises a random
copolymer such as those derived from copolymerization of two or more
different epoxides and carbon dioxide. In certain embodiments, such
APC-PEG triblock copolymers have a formula selected from the group
consisting of:

##STR00035## [0131] wherein R1 is a mixture of two or more
moieties selected from the group consisting of --H, methyl, ethyl,
C3-30 alkyl, CH2Cl, CF3, and CH2ORz. In certain
embodiments, R1 is a mixture of methyl and ethyl groups. In other
embodiments, R1 is a mixture of --H and methyl groups. In certain
embodiments, R1 is a mixture of methyl groups and C3-6 alkyl
groups. In certain embodiments, R1 is a mixture of methyl groups and
C6-24 alkyl groups.

[0132] In certain embodiments, provided triblock copolymers comprise
copolymers of poly(propylene glycol) (PPG) or a derivative thereof and
poly(propylene carbonate) (PPC) or derivatives thereof. In certain
embodiments, such copolymers have a formula selected from the group
consisting of:

##STR00036##

[0133] In certain embodiments, provided triblock copolymers comprise
copolymers of polypropylene glycol) (PPG) or a derivative thereof and
poly(ethylene carbonate) (PEC) or derivatives thereof. In certain
embodiments, these PPG-PEC triblock copolymers have a formula selected
from the group consisting of:

##STR00037##

[0134] In certain embodiments, provided triblock copolymers comprise
copolymers of an aliphatic polycarbonate (APC) and polypropylene glycol)
(PPG) or a derivative thereof, wherein the APC comprises a random
copolymer such as those derived from copolymerization of two or more
different epoxides and carbon dioxide. In certain embodiments, such
APC-PPG triblock copolymers have a formula selected from the group
consisting of:

##STR00038##

wherein, R1 is a mixture of two or more moieties selected from the
group consisting of --H, methyl, ethyl, C3-30 alkyl, CH2Cl,
CF3, and CH2ORz. In certain embodiments, R1 is a
mixture of methyl and ethyl groups. In other embodiments, R1 is a
mixture of --H and methyl groups. In certain embodiments, R1 is a
mixture of methyl groups and C3-6 alkyl groups. In certain
embodiments, R1 is a mixture of methyl groups and C6-24 alkyl
groups.

[0135] In certain embodiments, provided triblock copolymers comprise
copolymers of polyoxymethylene (POM) or a derivative thereof and
poly(propylene carbonate) (PPC) or derivatives thereof. In certain
embodiments, such copolymers have a formula selected from the group
consisting of:

##STR00039##

[0136] In certain embodiments, provided triblock copolymers comprise
copolymers of polyoxymethylene (POM) or a derivative thereof and
poly(ethylene carbonate) (PEC) or derivatives thereof. In certain
embodiments, these POM-PEC triblock copolymers have a formula selected
from the group consisting of:

##STR00040##

[0137] In certain embodiments, provided triblock copolymers comprise
copolymers of an aliphatic polycarbonate (APC) and polyoxymethylene (POM)
or a derivative thereof, wherein an APC comprises a random copolymer such
as those derived from copolymerization of two or more different epoxides
and carbon dioxide. In certain embodiments, such APC-POM triblock
copolymers have a formula selected from the group consisting of:

##STR00041##

wherein, [0138] R1 is a mixture of two or more moieties selected
from the group consisting of --H, methyl, ethyl, C3-30 alkyl,
CH2Cl, CF3, and CH2ORz. In certain embodiments,
R1 is a mixture of methyl and ethyl groups. In other embodiments,
R1 is a mixture of --H and methyl groups. In certain embodiments,
R1 is a mixture of methyl groups and C3-6 alkyl groups. In
certain embodiments, R1 is a mixture of methyl groups and C6-24
alkyl groups.

[0139] In certain embodiments, provided polymers are triblock copolymers
having an aliphatic polycarbonate central block flanked by two
hydrophilic oligomers. In certain embodiments, such triblock copolymers
have the formula B-A-B, where -A- is a polycarbonate or
polyethercarbonate chain having from about 3 to about 500 repeating units
and each B is independently a hydrophilic oligomer having from about 4 to
about 200 repeating units.

[0140] In certain embodiments, such B-A-B triblock copolymers have the
formula XI:

##STR00042## [0141] where Ra, Rb, Rc, Rd, n, L, Z,
Y, and m are as defined above, and where m' is, on average approximately
equal to m.

[0150] In certain embodiments, in polymers of formulae XI through XI-b, Y
is --H. In certain embodiments, in polymers of formulae XI through XI-b,
Y is an optionally substituted aliphatic group. In certain embodiments, Y
is selected from the group consisting of methyl, ethyl, n-propyl,
i-propyl, n-butyl, sec-butyl, t-butyl, allyl and benzyl. In certain
embodiments, in polymers of formulae XI through XI-b, Y is an acyl group.
In certain embodiments, Y is selected from the group consisting of
formate, acetate, trifluoroacetate, propionate, and optionally
substituted benzoate. In certain embodiments, in polymers of formulae XI
through XI-b, Y is --Si(R10)3. In certain embodiments, in
polymers of formulae XI through XI-b, Y is a silyl group. In certain
embodiments, Y is selected from the group consisting of trimethylsilyl,
triethylsilyl, triisopropyl silyl, t-butyldimethylsilyl, and
t-butyldiphenylsilyl. In certain embodiments, in polymers of formulae XI
through XI-b, Y is a sulfonate group.

[0151] In certain embodiments, in polymers of formulae XI-b through XI-d,
R100 is absent (e.g. the polycarbonate chain comprises poly(ethylene
carbonate). In certain embodiments, in polymers of formulae XI-b through
XI-d, R100 is a methyl group. In certain embodiments, in polymers of
formulae XI-b through XI-d, R100 is an ethyl group. In certain
embodiments, in polymers of formulae XI-b through XI-d, R100 is a
random mixture of methyl and ethyl groups. In certain embodiments, in
polymers of formulae XI-b through XI-d, R100 is a chloromethyl
group. In certain embodiments, in polymers of formulae XI-b through XI-d,
R100 is a random mixture of methyl and chloromethyl groups. In
certain embodiments, in polymers of formulae XI-b through XI-d, R100
is a random mixture of methyl and one or more C3-30 alkyl groups.

[0152] In certain embodiments, in polymers of formulae XI-b through XI-d,
R100 is a --CH2ORz group. In certain embodiments, a
CH2ORz group comprises an ether group (e.g. the polycarbonate
chain is a poly(glycidyl ether carbonate)). In some embodiments, a
CH2ORz group comprises an ester group (e.g. the polycarbonate
chain is a poly(glycidyl ester carbonate)). In certain embodiments,
R100 is a random mixture of --H and --CH2ORz groups. In
certain embodiments, R100 is a random mixture of C1-4 alkyl
groups and --CH2ORz groups. In certain embodiments, R100
is a random mixture of methyl and --CH2ORz groups.

[0153] In certain embodiments, provided polymer compositions comprise
polymer chains of formulae XI through XI-d above wherein the value of n
is, on average, between about 3 and about 200. In certain embodiments,
the value of n is, on average between about 3 and about 100. In certain
embodiments, the value of n is, on average between about 3 and about 50.
In certain embodiments, the value of n is, on average between about 3 and
about 25. In certain embodiments, the value of n is, on average between
about 10 and about 20. In certain embodiments, the value of n is, on
average between about 3 and about 10.

[0154] In certain embodiments, provided polymer compositions comprise
polymer chains of formulae XI through XI-d above wherein the value of m
is, on average, between about 4 and about 500. In certain embodiments,
the value of m is, on average between about 5 and about 200. In certain
embodiments, the value of m is, on average between about 5 and about 50.
In certain embodiments, the value of m is, on average between about 5 and
about 25. In certain embodiments, the value of m is, on average between
about 10 and about 20. In certain embodiments, the value of n is, on
average between about 5 and about 10.

[0155] In certain embodiments, where the polymer has one of the formulae
XI-b through XI-d, R100 is present, and the head to tail ratio of
adjacent

##STR00047##

groups is greater than about 80%. In certain embodiments, the head to
tail ratio is greater than about 90%. In certain embodiments, the head to
tail ratio is greater than about 92%. In certain embodiments, the head to
tail ratio is greater than about 95%.

[0156] In certain embodiments, copolymers B-A-B have narrow
polydisperisity indices. In some embodiments, the PDI of provided block
copolymers is less than about 2. In certain embodiments, the PDI is less
than 1.5. In some embodiments, the PDI is less than 1.4, less than 1.2 or
less than about 1.1.

[0157] In certain embodiments, for each of the formulae described herein,
R10 is optionally substituted C1-20 aliphatic. In some
embodiments, R10 is C1-12 heteroaliphatic. In some embodiments,
R10 is 6- to 14-membered aryl. In some embodiments, R10 is 5-
to 14-membered heteroaryl. In some embodiments, R10 is C1-12
heteroaliphatic. In some embodiments, R10 is methyl.

Polyether-Polycarbonates

[0158] In certain embodiments, provided copolymers are amphiphilic block
copolymers wherein the carbonate-containing portion of the polymer
comprises a polycarbonate containing both carbonate and ether linkages.
In certain embodiments, a polymer A-L-B comprises a random
poly(ether-co-carbonate) and has the formula VI:

##STR00048##

where X, B, Ra, Rb, Rc, Rd, L, and n are as defined
above.

[0159] It will be appreciated that in chemical formulae described herein,
a dashed line "" means that the repeating unit on either side of the line
occurs randomly throughout the polymer block contained within the
parentheses between which the dashed line appears.

[0160] In certain embodiments, a polymer A-L-B has the formula VI-a:

##STR00049##

[0161] where X, L, B, R100, and n are as defined above.

[0162] In certain embodiments, a polymer A-L-B has the formula VII:

##STR00050## [0163] where X, L, R100, n and m are as defined
above.

[0164] In certain embodiments, a polymer A-L-B has the formula VII-a:

##STR00051## [0165] where X, R100, n and m are as defined above.

[0166] In certain embodiments, a polymer A-L-B has the formula VII-b:

##STR00052## [0167] where X, n and m are as defined above.

[0168] In certain embodiments, a polymer A-L-B has the formula VII-c:

##STR00053## [0169] where X, n and m are as defined above.

[0170] In certain embodiments, a polymer A-L-B has the formula VII-d:

##STR00054##

[0171] In certain embodiments, a polymer A-L-B has the formula VII-e:

##STR00055##

[0172] In certain embodiments, a polymer A-L-B has the formula VII-f:

##STR00056## [0173] where n and m are as defined above.

[0174] In certain embodiments, a polymer A-L-B has the formula VII-g:

##STR00057##

[0175] In certain embodiments, a polymer A-L-B has the formula VII-h:

##STR00058##

[0176] In certain embodiments, a polymer A-L-B has the formula VII-i:

##STR00059## [0177] where n and m are as defined above.

[0178] In certain embodiments, a polymer A-L-B has the formula VII-j:

##STR00060##

[0179] In certain embodiments, a polymer A-L-B has the formula VII-k:

##STR00061##

[0180] In certain embodiments, a polymer A-L-B has the formula VIII:

##STR00062## [0181] where X, L, R100, n and m are as defined
above.

[0182] In certain embodiments, a polymer A-L-B has the formula VIII-a:

##STR00063## [0183] where X, R100, n and m are as defined above.

[0184] In certain embodiments, a polymer A-L-B has the formula VIII-b:

##STR00064## [0185] where X, n and m are as defined above.

[0186] In certain embodiments, a polymer A-L-B has the formula VIII-c:

##STR00065## [0187] where n and m are as defined above.

[0188] In certain embodiments, a polymer A-L-B has the formula VIII-d:

##STR00066##

[0189] In certain embodiments, a polymer A-L-B has the formula VIII-e:

##STR00067##

[0190] In certain embodiments, a polymer A-L-B has the formula VIII-f:

##STR00068## [0191] where n and m are as defined above.

[0192] In certain embodiments, a polymer A-L-B has the formula VIII-g:

##STR00069##

[0193] In certain embodiments, a polymer A-L-B has the formula VIII-h:

##STR00070##

[0194] In certain embodiments, a polymer A-L-B has the formula IX:

##STR00071## [0195] where X, n and m are as defined above.

[0196] In certain embodiments, a polymer A-L-B has the formula IX-a:

##STR00072## [0197] where n and m are as defined above.

[0198] In certain embodiments, a polymer A-L-B has the formula IX-b:

##STR00073##

[0199] In certain embodiments, a polymer A-L-B has the formula IX-c:

##STR00074##

[0200] In certain embodiments, a polymer A-L-B has the formula IX-d:

##STR00075## [0201] where n and m are as defined above.

[0202] In certain embodiments, a polymer A-L-B has the formula IX-e:

##STR00076##

[0203] In certain embodiments, a polymer A-L-B has the formula IX-f:

##STR00077##

[0204] In certain embodiments, provided triblock copolymers have the
formula A-B-A wherein A is a polycarbonate chain containing both
carbonate and ether linkages has the formula (IX-g):

[0206] As mentioned above, in some embodiments, provided copolymers have a
high percentage of carbonate linkages and a low percentage of ether
linkages. In certain embodiments, for copolymers of formulae VI through
IX-g, the proportion of ether linkages in the polyethercarbonate is less
than about 50%. In certain embodiments, for copolymers of formulae VI
through IX-g, the proportion of ether linkages in the polyethercarbonate
is less than about 46%. In certain embodiments, for copolymers of
formulae VI through IX-g, the proportion of ether linkages in the
polyethercarbonate is less than about 40%. In certain embodiments, for
copolymers of formulae VI through IX-g, the proportion of ether linkages
in the polyethercarbonate is less than about 30%. In certain embodiments,
for copolymers of formulae VI through IX-g, the proportion of ether
linkages in the polyethercarbonate is less than about 20%. In certain
embodiments, for copolymers of formulae VI through IX-g, the proportion
of ether linkages in the polyethercarbonate is less than about 10%. In
certain embodiments, for copolymers of formulae VI through IX-g, the
proportion of ether linkages in the polyethercarbonate is less than about
5%. In certain embodiments, for copolymers of formulae VI through IX-g,
the proportion of ether linkages in the polyethercarbonate is less than
about 1%. In certain embodiments, for copolymers of formulae VI through
IX-g, the proportion of ether linkages in the polyethercarbonate is less
than about 0.1%.

[0207] In some embodiments, provided polymer compositions have an average
molecular weight between 200 and 10,000 g/mol. In some embodiments,
provided polymer compositions have an average molecular weight between
200 and 5,000 g/mol. In some embodiments, provided polymer compositions
have an average molecular weight between 500 and 2,500 g/mol. In some
embodiments, provided polymer compositions have an average molecular
weight between 800 and 2,000 g/mol. In some embodiments, provided polymer
compositions have an average molecular weight between 500 and 1,000
g/mol. In some embodiments, provided polymer compositions have an average
molecular weight between 1,000 and 2,000 g/mol. In some embodiments,
provided polymer compositions have an average molecular weight between
1,000 and 5,000 g/mol. In some embodiments, provided polymer compositions
have an average molecular weight between 200 and 1,000 g/mol.

[0208] In certain embodiments, a block copolymer is provided in a quantity
of less than 5 weight % relative to the CO2 phase. In certain
embodiments, the block copolymer is provided in a quantity of less than 1
weight %. In certain embodiments, the block copolymer is provided in a
quantity of less than 0.5 weight %. In certain embodiments, the block
copolymer is provided in a quantity of less than 0.1 weight %. In certain
embodiments, the block copolymer is provided in a quantity of less than
0.05 weight %. In certain embodiments, the block copolymer is provided in
a quantity of about 0.01 weight %.

[0209] In some embodiments, a provided copolymer composition has a
solubility in supercritical CO2 of at least 0.01 weight % at a
pressure of 4,000 psi or higher. In some embodiments, a provided
copolymer composition has a solubility in supercritical CO2 of at
least 0.05 weight % at a pressure of 4,000 psi or higher. In some
embodiments, a provided copolymer composition has a solubility in
supercritical CO2 of at least 0.1 weight % at a pressure of 4,000
psi or higher. In some embodiments, a provided copolymer composition has
a solubility in supercritical CO2 of at least 0.2 weight % at a
pressure of 4,000 psi or higher. In some embodiments, a provided
copolymer composition has a solubility in supercritical CO2 of at
least 0.5 weight % at a pressure of 4,000 psi or higher. In some
embodiments, a provided copolymer composition has a solubility in
supercritical CO2 of at least 1.0 weight % at a pressure of 4,000
psi or higher. In some embodiments, a provided copolymer composition has
a solubility in supercritical CO2 of at least 0.01 weight % at a
pressure of 3,000 psi or higher. In some embodiments, a provided
copolymer composition has a solubility in supercritical CO2 of at
least 0.05 weight % at a pressure of 3,000 psi or higher. In some
embodiments, a provided copolymer composition has a solubility in
supercritical CO2 of at least 0.1 weight % at a pressure of 3,000
psi or higher. In some embodiments, a provided copolymer composition has
a solubility in supercritical CO2 of at least 0.2 weight % at a
pressure of 3,000 psi or higher. In some embodiments, a provided
copolymer composition has a solubility in supercritical CO2 of at
least 0.5 weight % at a pressure of 3,000 psi or higher. In some
embodiments, a provided copolymer composition has a solubility in
supercritical CO2 of at least 1.0 weight % at a pressure of 3,000
psi or higher. In some embodiments, a provided copolymer composition has
a solubility in supercritical CO2 of at least 0.01 weight % at a
pressure of 2,000 psi or higher. In some embodiments, a provided
copolymer composition has a solubility in supercritical CO2 of at
least 0.05 weight % at a pressure of 2,000 psi or higher. In some
embodiments, a provided copolymer composition has a solubility in
supercritical CO2 of at least 0.1 weight % at a pressure of 2,000
psi or higher. In some embodiments, a provided copolymer composition has
a solubility in supercritical CO2 of at least 0.2 weight % at a
pressure of 2,000 psi or higher. In some embodiments, a provided
copolymer composition has a solubility in supercritical CO2 of at
least 0.5 weight % at a pressure of 2,000 psi or higher. In some
embodiments, a provided copolymer composition has a solubility in
supercritical CO2 of at least 1.0 weight % at a pressure of 2,000
psi or higher. In some embodiments, a provided copolymer composition has
a solubility in supercritical CO2 of at least 0.01 weight % at a
pressure of 1,000 psi or higher. In some embodiments, a provided
copolymer composition has a solubility in supercritical CO2 of at
least 0.05 weight % at a pressure of 1,000 psi or higher. In some
embodiments, a provided copolymer composition has a solubility in
supercritical CO2 of at least 0.1 weight % at a pressure of 1,000
psi or higher. In some embodiments, a provided copolymer composition has
a solubility in supercritical CO2 of at least 0.2 weight % at a
pressure of 1,000 psi or higher. In some embodiments, a provided
copolymer composition has a solubility in supercritical CO2 of at
least 0.5 weight % at a pressure of 1,000 psi or higher. In some
embodiments, a provided copolymer composition has a solubility in
supercritical CO2 of at least 1.0 weight % at a pressure of 1,000
psi or higher.

[0210] In some embodiments, provided copolymers form polymersomes. Having
read the present disclosure, one of ordinary skill in the art would be
able to carry out routine experimentation to form polymersomes from
provided amphiphilic copolymers. Using methods well known to the skilled
artisan, parameters such as polymer concentration, solvent, temperature,
and various physical means (e.g., shearing, dialysis, etc.) can be
applied to achieve vesicle formation. Depending upon the desired use of
the vesicle (e.g., drug delivery, viscosifying agent, etc.), the skilled
artisan will select the appropriate copolymer to achieve the desired
polymersome properties.

[0211] One of ordinary skill will also be familiar with a variety of
characterization techniques that can be used to determine the degree of
vesicle formation. For example, Tm, scanning electron microscopy,
transmission electron microscopy, dynamic stress rheometer, and dynamic
light scattering, to name but a few, are all routine techniques in
characterizing polymersome vesicles. Further guidance can be found in
U.S. Pat. Appl. Publication 2005/0215438.

[0212] Certain polymers of the present invention can be produced by
copolymerization of carbon dioxide and epoxides using catalysts adapted
from those disclosed in U.S. Pat. Nos. 6,870,004; and 7,304,172, in
pending PCT application Nos. PCT/US09/56220, PCT/US09/54773, and in
published PCT applications WO2008136591A1 and WO2008150033A1, the
entirety of each of which is incorporated herein by reference.

[0213] In certain methods of the present invention, the methods include
synthesizing a polymer by reacting an epoxide and carbon dioxide in the
presence of a suitable catalyst and a polyether chain transfer agent
having one free OH group as shown in Scheme 1:

##STR00079##

[0214] The method of Scheme 1 is suitable for the synthesis of compounds
described above wherein the polyether moiety is capped with a Y group
that is not --H, and the polycarbonate chain is terminated with an OH
group. Experimental conditions and methods suitable for this process are
described more fully in the Examples section below, and in co-pending
International Patent Application No. PCT/US2009/056220, filed Sep. 8,
2009, the entire contents of which are hereby incorporated by reference.

[0215] The products of Scheme 1 can be further modified by reactions well
known to those skilled in the art of organic synthesis such as
alkylation, acylation, sulfonation, or silylation to yield compounds
wherein the polycarbonate chain is capped with a non-OH end group. This
is shown in Scheme 2:

##STR00080##

[0216] It will be appreciated that there are many possible variations
encompassed by the synthetic approaches detailed in Schemes 1-5,
including the choice of suitable protecting (capping) chemistries for the
polymer termini. Suitable hydroxyl and carboxyl protecting groups are
well known in the art and include those described in detail in Protecting
Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rd
edition, John Wiley & Sons, 1999, the entirety of which is incorporated
herein by reference.

[0217] For example, where it is desired that the polyether portion of such
polymers have a free OH group, the polyether chain transfer agent of
Scheme 1 can be chosen to contain on one terminus a labile group that can
be removed after construction of the block co-polymer. Exemplary
approaches include the use of mono-benzyl or mono-allyl polyether
starting material followed by hydrogenolysis of the benzyl or allyl ether
after construction of the copolymer. Another viable approach is the use
of a monosilylated polyether chain transfer agent followed by fluoride
mediated cleavage of the silyl ether after construction of the copolymer.
It will be appreciated that numerous other hydroxyl protecting groups
that can be cleaved under relatively mild conditions are known in the art
and can be used to similar effect in accordance with the present
disclosure.

[0218] In certain embodiments, it is desirable to have a free --OH group
on the hydrophilic polyether portion of the block co-polymer and a non-OH
end-group on the polycarbonate. Polymers of this type can be produced
using the methods just described by capping the --OH group of the
polycarbonate as described above and shown in Scheme 2, followed by
removal of a suitably chosen protecting group on the polyether block of
the copolymer as just described.

[0219] For block copolymers comprising polycarbonates derived from
monosubstituted epoxides, it will be appreciated that there are different
regiochemical arrangements possible for the orientation of the
polycarbonate chain relative to the polyether. For example, the two
compounds shown below are both block co-polymers of PEG and polypropylene
carbonate):

##STR00081##

[0220] Compound (A) is typical of the product formed using the method
shown in Scheme 1, where the epoxide is propylene oxide. The
directionality of the epoxide enchainment during the polymerization will
be predominately (>60%) from the less hindered ring carbon, therefore
the last enchained epoxide which comprises the chain terminus at the end
of synthesis will be oriented predominately as shown in the first
structure. If one uses a complementary approach described below in Scheme
5, wherein a preformed monofunctional polycarbonate chain is ligated to a
polyether chain, the regiochemistry will be predominantly as shown in
structure (B) since a mono-hydroxy terminated polypropylene carbonate)
chain resulting from initiation by a moiety X, will have predominately
secondary OH groups at the reactive terminus. Reaction of these OH groups
to ligate or initiate a polyether chain will result predominantly (e.g.
>60%) in the regiochemistry shown in compound (B). It will be
appreciated that this phenomenon is observed also with the use of other
epoxide substrates such as butylene oxide, epichlorohydrin, and glycidol
derivatives, but not with unsubstituted, or symmetrically substituted
epoxides such as ethylene oxide or 2-butene oxide.

[0221] In certain embodiments of the present invention, the methods
include synthesizing a triblock copolymer by reacting an epoxide and
carbon dioxide in the presence of a suitable catalyst and a polyether
chain transfer agent having two free OH group as shown in Scheme 3.
Compounds of formulae X through X-d described above can be made according
to this method.

##STR00082##

[0222] As shown in scheme 4, the products of Scheme 3, can be end-capped
as described above for diblock co-polymers.

##STR00083##

[0223] It will be appreciated that these methods can also be applied using
other --OH or CO2H terminated oligomers as chain transfer agents in
place of the polyethers depicted above. For example, polyesters,
polyacrylates, or propoxylated or ethoxylated derivatives thereof can be
used as well.

[0224] In some embodiments, the present disclosure encompasses methods of
making amphiphilic polymers as described hereinabove comprising the step
of synthesizing a polycarbonate chain having one end terminated with an
--OH group, followed by ligation to a polyether. Such ligation may be
accomplished by forming an ether bond to a preformed polyether molecule
or, more preferably, by conducting a second polymerization in the
presence of a suitable polyether precursor such as an epoxide or
formaldehyde to synthesize the polyether block directly onto the
co-polymer. This approach is outlined in Scheme 5.

##STR00084##

[0225] It will be appreciated that this approach leads to compounds having
an --OH terminal group on the polyether block and a non-OH group derived
from the polycarbonate chain initiator at the polycarbonate terminus of
the polymer.

[0226] Similarly, triblock co-polymers derived from ether synthesis upon a
di-hydroxy terminated polycarbonate are also possible, this process will
yield compounds of formula XI-b described hereinabove.

[0227] For block co-polymers made by polymerizing a polyether precursor
onto a preformed polycarbonate, it should be noted that the resulting
compounds may contain a linker between the polycarbonate and the
polyether corresponding to a ring-opened molecule of the epoxide from
which the polycarbonate was formed. This is shown in structure (C) below
for a polycarbonate-co-polyethylene glycol where the linker is denoted
"L" and in other similar examples hereinabove.

##STR00085##

[0228] Of course, in cases where the epoxide subunit of the polycarbonate
corresponds to the repeat unit of a polyether block (i.e. poly(ethylene
carbonate)-block-poly(ethylene glycol)), such a linker moiety will not be
distinguishable and the linker `L` can be regarded as comprising a single
covalent bond.

[0229] In some embodiments, the present invention encompasses methods for
the formation of emulsions between supercritical carbon dioxide and a
polar liquid. In certain embodiments, the polar liquid comprises water or
an aqueous solution. In certain embodiments, the method includes the step
of agitating a biphasic mixture of supercritical CO2 and the polar
liquid in the presence of any one or more of the block copolymers
described hereinabove. In another embodiment, the method of forming the
emulsion comprises forcing a mixture of the two phases and the surfactant
through a porous substance.

[0230] In certain embodiments, the present invention provides a method of
forming an emulsion of supercritical CO2 and an aqueous phase, the
method comprising a step of agitating supercritical CO2 and the
aqueous phase in the presence of a block copolymer having a formula:

##STR00086##

wherein [0231] X is selected from the group consisting of: halogen;
--OH; azide, nitrile, and --ORz; [0232] each Ra, Rb,
Rc, and Rd is independently selected from the group consisting
of: hydrogen, halogen, --CH2ORz, optionally substituted
C1-10 aliphatic, optionally substituted 6- to 14-membered aromatic,
optionally substituted 3- to 14-membered heterocyclic, and optionally
substituted 5- to 14-membered heteroaryl, and where any two or more of
Ra, Rb, Rc, and Rd may Re taken together to form
an optionally substituted 3- to 12-membered ring, optionally containing
one or more heteroatoms; [0233] L is a bond or a polyfunctional moiety,
[0234] B is a hydrophilic oligomer having from about 4 to about 100
repeating units, [0235] n is an integer between 4 and 100, [0236] Rz
is selected from the group consisting of --C(O)R10,
--SO2R10, --Si(R10)3, --C(O)N(R10)2,
optionally substituted C1-12 aliphatic; optionally substituted
C1-12 heteroaliphatic; optionally substituted 6- to 14-membered
aryl; and optionally substituted 5- to 14-membered heteroaryl, and [0237]
R10 is an optionally substituted moiety selected from the group
consisting of: C1-20 aliphatic; C1-12 heteroaliphatic; 6- to
14-membered aryl; and 5- to 14-membered heteroaryl.

[0238] In certain embodiments, the present invention provides a method of
forming an emulsion of supercritical CO2 and an aqueous phase, the
method comprising a step of agitating supercritical CO2 and the
aqueous phase in the presence of a block copolymer having a formula:

##STR00087##

wherein [0239] X' is selected from the group consisting of --OH, and
--ORz, [0240] R100 is optionally present, and if present is
selected from the group consisting of --CH3, --CF3,
--CH2CH3, --CH2ORz, and --CH2Cl, [0241] each n
is independently an integer between 4 and 100, [0242] --Z-- is an
optionally substituted C1-6 aliphatic group, [0243] m is an integer
between 5 and 200, [0244] Rz is selected from the group consisting
of --C(O)R10, --SO2R10, --Si(R10)3,
--C(O)N(R10)2, optionally substituted C1-12 aliphatic;
optionally substituted C1-12 heteroaliphatic; optionally substituted
6- to 14-membered aryl; and optionally substituted 5- to 14-membered
heteroaryl, and [0245] R10 is at each occurrence an optionally
substituted moiety independently selected from the group consisting of:
C1-12 aliphatic; C1-12 heteroaliphatic; 6- to 14-membered aryl;
and 5- to 14-membered heteroaryl.

[0246] In certain embodiments, provided block co-polymers useful for
forming an emulsion are of the formula:

##STR00088##

wherein [0247] R100 is optionally present, and if present is
selected from the group consisting of --CH3, --CF3,
--CH2CH3, --CH2ORz, --CH2Cl, a C6-30 alkyl
group, and mixtures of any two or more of these.

[0248] In certain embodiments, the block copolymers and methods described
hereinabove have utility in modifying the viscosity of supercritical
CO2 water mixtures. Such viscosity modifying properties can have
utility in the use of supercritical CO2 as a fluid for secondary or
tertiary recovery of product from oil wells. Methods of using and means
of modeling compounds for such applications are described in published
PCT application WO 2000035998 A2 which is incorporated herein by
reference and in references cited therein.

[0249] In some embodiments, the present invention provides a method of
modifying the viscosity of a fluid comprising a mixture of supercritical
CO2 and water, the method comprising a step of agitating the mixture
in the presence of a block copolymer having a formula:

##STR00089##

wherein [0250] X is selected from the group consisting of: halogen;
--OH; azide, nitrile, and --ORz; [0251] each Ra, Rb,
Rc, and Rd is independently selected from the group consisting
of: hydrogen, halogen, --CH2ORz, optionally substituted
C1-10 aliphatic, optionally substituted 6- to 14-membered aromatic,
optionally substituted 3- to 14-membered heterocyclic, and optionally
substituted 5- to 14-membered heteroaryl, and where any two or more of
Ra, Rb, Rc, and Rd may be taken together to form an
optionally substituted 3- to 12-membered ring, optionally containing one
or more heteroatoms; [0252] L is a bond or a polyfunctional moiety,
[0253] B is a hydrophilic oligomer having from about 4 to about 100
repeating units, [0254] n is an integer between 4 and 100, [0255] Rz
is selected from the group consisting of --C(O)R10,
--SO2R10, --Si(R10)3, --C(O)N(R10)2,
optionally substituted C1-12 aliphatic; optionally substituted
C1-12 heteroaliphatic; optionally substituted 6- to 14-membered
aryl; and optionally substituted 5- to 14-membered heteroaryl, and [0256]
R10 is an optionally substituted moiety selected from the group
consisting of: C1-20 aliphatic; C1-12 heteroaliphatic; 6- to
14-membered aryl; and 5- to 14-membered heteroaryl.

[0257] In certain embodiments, the present invention provides a method of
modifying the viscosity of a fluid comprising a mixture of supercritical
CO2 and water, the method comprising a step of agitating the mixture
in the presence of a block copolymer having a formula:

##STR00090##

wherein [0258] X' is selected from the group consisting of --OH, and
--ORz[0259] R100 is optionally present, and if present is
selected from the group consisting of --CH3, --CF3,
--CH2CH3, --CH2ORz, and --CH2Cl; [0260] each n
is independently an integer between 4 and 100, [0261] --Z-- is an
optionally substituted C1-6 aliphatic group, [0262] m is an integer
between 5 and 200, [0263] Rz is selected from the group consisting
of --C(O)R10, --SO2R10, --Si(R10)3,
--C(O)N(R10)2, optionally substituted C1-12 aliphatic;
optionally substituted C1-12 heteroaliphatic; optionally substituted
6- to 14-membered aryl; and optionally substituted 5- to 14-membered
heteroaryl, and [0264] R10 is at each occurrence an optionally
substituted moiety independently selected from the group consisting of:
C1-12 aliphatic; C1-12 heteroaliphatic; 6- to 14-membered aryl;
and 5- to 14-membered heteroaryl.

[0265] In certain embodiments of the methods described above, a block
copolymer is provided as a solution in supercritical CO2.

[0266] In certain embodiments, the present invention includes methods of
enhancing product recovery from oil wells by introducing any of the
above-described polymers to an oil-containing geological formation. In
some embodiments, such methods comprise the step of pumping a provided
copolymer into an oil well. In certain embodiments, the polymers are
introduced in combination with supercritical CO2. In certain
methods, the supercritical CO2 is combined with water or brine to
form an emulsion capable of flushing trapped oil from geological
formations.

[0267] (a compound of formula II-d wherein X' is OH, R100 is
--CH3, L is a bond, and Z is --CH2CH2-- and Y' is CH3
with n being approximately 11 and m being approximately 11)

##STR00092##

[0268] Procedure A:

[0269] A 3 oz. Fischer-Porter bottle was fitted with a pressure head and
magnetic stirrer. The reaction vessel was dried in vacuo using a heat gun
and cooled to rt. catalyst C-I (24 mg, 3.6×10-5 mol) and
bis(triphenylphosphine)iminium chloride (21 mg, 3.6×10-5 mol)
were charged to the reaction vessel. The vessel was evacuated for 15 min,
then backfilled with nitrogen. This procedure was repeated twice more.
While under the positive flow of nitrogen, propylene oxide (20 mL, 0.29
mol) and poly(ethylene glycol) methyl ether (Mn=550 g/mol, 2.2 mL,
7.1×10-3 mol) were charged to the reaction vessel. The
reaction was placed into a 30° C. water bath, stirred, and
pressurized with carbon dioxide (100 psi).

[0270] After 21.5 h the reaction was vented and quenched with a methanolic
solution (3 mL) of tosic acid (14 mg, 7.2×10-5 mol). The
reaction was stirred for 10 min at rt and the unreacted propylene oxide
was removed by evaporation. The resulting polymer was diluted with
acetone (10 mL) and filtered through filter paper to remove solids. The
filtrate was shaken with Dowex MSC (H) (5.0 g) for 2 h and filtered
through a fine mesh. The filtrate was concentrated, in vacuo, to produce
1.0 g (4% yield) of a tan, slightly viscous polymer (Mw=1,688 g/mol,
Mw/Mn=1.06; Td(onset)=210° C., containing 24%
propylene carbonate).

[0271] Procedure B:

[0272] A 300 mL stainless steel reactor was dried, in vacuo, using a hot
plate (120° C.) and cooled to rt. catalyst C-I (60 mg,
8.9×10-5 mol) and bis(triphenylphosphine)iminium chloride (51
mg, 8.9×10-5 mol) were charged to the reaction vessel. The
vessel was evacuated for 15 min, then backfilled with nitrogen. This
procedure was repeated twice more.

[0273] While under the positive flow of nitrogen, propylene oxide (50 mL,
0.71 mol) and poly(ethylene glycol) monomethylether (Mn=550 g/mol,
4.5 mL, 8.9×10-3 mol) were charged to the reaction vessel. The
reaction was pressurized to 300 psi of carbon dioxide and heated to
30° C. using a heating mantle.

[0274] After 16 h the reaction was vented and quenched with a methanolic
solution (3 mL) of tosic acid (approx. 34 mg, 1.8×10-4 mol).
The reaction was stirred for 10 min at rt and the unreacted propylene
oxide was removed by evaporation. The resulting polymer samples were
diluted with acetone (100 mL) and filtered through filter paper to remove
solids. The filtrate was shaken with Dowex MSC (H) (9.0 g) for 2 h and
filtered through a fine mesh. The filtrate was concentrated, in vacuo, to
produce a total of 11.5 g (16% yield) of a tan viscous polymer
(Mw=3,057 g/mol, Mw/Mn=1.06; Tg=-34° C.;
Td(onset)=252° C., 7% propylene carbonate).

[0279] A 300 mL stainless steel reactor was dried, in vacuo, using a hot
plate (120° C.) and cooled to rt. Catalyst C-I (182 mg,
2.7×10-4 mol) and Bis(triphenylphosphine)iminium chloride (154
mg, 2.7×10-4 mol) were charged to the reaction vessel. The
vessel was evacuated for 15 min, then backfilled with nitrogen. This
procedure was repeated twice more. While under the positive flow of
nitrogen, propylene oxide (150 mL, 2.2 mol) and poly(ethylene glycol)
(Mn=400 g/mol, 9.5 mL, 2.7×10-2 mol) were charged to the
reaction vessel. The reaction was pressurized to 300 psi of carbon
dioxide and heated to 30° C. using a heating mantle.

[0281] ##STR00097## [0282] (a compound of formula II-c wherein X' is
--OAc, R100 is --CH3, L is a bond, and Z is
--CH2CH2-- and Y' is --H)

##STR00098##

[0283] A 3 oz. Fischer-Porter bottle is fitted with a pressure head and
magnetic stirrer. The reaction vessel is dried in vacuo using a heat gun
and cooled to rt. Catalyst C-I (24 mg, 3.6×10-5 mol) and
bis(triphenylphosphine)iminium chloride (21 mg, 3.6×10-5 mol)
are charged to the reaction vessel. The vessel is evacuated for 15 min,
then backfilled with nitrogen. While under a positive flow of nitrogen,
propylene oxide (20 mL, 0.29 mol) and poly(ethylene glycol) mono
t-butyldimethylsilyl ether (7.1×10-3 mol prepared as described
in Journal of Organic Chemistry (1991), 56(13), 4326-4329) are charged to
the reaction vessel. The reaction is placed into a 30° C. water
bath, stirred, and pressurized with carbon dioxide (100 psi).

[0284] After 24 h the reaction is vented and quenched with a methanolic
solution (3 mL) of tosic acid (14 mg, 7.2×10-5 mol). The
mixture is stirred for 10 min at rt and the unreacted propylene oxide is
removed by evaporation. The resulting polymer is diluted with acetone (10
mL) and filtered through filter paper to remove solids. The filtrate is
shaken with Dowex MSC (H) (5.0 g) for 2 h and filtered through a fine
mesh. The filtrate is concentrated, in vacuo, to produce polymer 4a. This
polymer is dissolved in dichloromethane (10 mL) containing triethyl amine
(1 mL) and treated with acetic anhydride (0.5 mL). The mixture is heated
to reflux for 16 h, then cooled to rt, diluted with dichloromethane (40
mL) and washed with water and then brine. The dichloromethane solution is
dried on anhydrous K2CO3 and concentrated to give compound 4b.
Polymer 4b is dissolved in THF (20 mL) in a PTFE container and
tetrabutylammonium fluoride (0.2 g) is added. The mixture is stirred for
1 h, then poured into water and extracted with dichloromethane
(5×20 mL). The combined dichloromethane extracts are dried on
K2CO3, filtered and concentrated to afford polymer 4.

[0285] ##STR00099## [0286] (a compound of formula II-d wherein X' is
pivaloyl, R100 is --CH3, L is a bond, Z is
--CH(CH3)CH2-- and Y' is --H)

##STR00100##

[0287] Compound 5 is synthesized under conditions similar to those
described in Example 4, except mono-TMS-protected polypropylene glycol is
used as the starting material, and pivaloyl chloride is substituted for
acetic anhydride.

[0290] In a glovebox, catalyst C-II (5.4 mg) and PPN-acetate (4.8 mg) are
charged to an oven-dried 20 mL glass liner. The liner is inserted into a
stainless steel high pressure reactor. The system is purged with N2
five times and purged with CO2 twice. While under the positive flow
of CO2, propylene oxide (5 mL) and acetic acid (200 μL) are
charged to the reaction vessel. The reaction is heated to 50° C.,
then pressurized with carbon dioxide (300 psi) and stirred. After 6 h the
reaction is vented and quenched with acidic methanol (0.2 mL). The
reaction is cooled to room temperature, and the resulting polymer is
diluted with acetone (5 mL) and transferred to a foil pan. The unreacted
propylene oxide and acetone are removed by evaporation to produce polymer
7a as an oil.

[0291] In a dry 100 ml flask, 1 g of polymer 7a is dissolved in 15 mL of
dichloromethane. To this mixture is added 2 g of ethylene oxide followed
by 150 mg of catalyst C-III dissolved in 5 mL of dichloromethane. This
mixture is stirred at rt for 48 h, then quenched by addition of a large
excess of methanol. The volatile components are then removed under
vacuum, the residue is dissolved in THF (100 mL) and filtered through a
0.22 μm filter. Evaporation of the filtrate provides polymer 7 as a
viscous oil.

[0292] ##STR00103## [0293] (a compound of formula II-c wherein X is
--O-i-Pr, R100 is --CH3, L is a bond, and Z is
--CH2CH(CH3)--)

##STR00104##

[0294] In a glovebox, catalyst C-II (50 mg) and PPN-chloride (48 mg) are
charged to an oven-dried 200 mL high pressure reactor. The reactor is
purged with N2 five times and purged with CO2 twice. While
under the positive flow of CO2, propylene oxide (70 mL) and
isopropyl alcohol (0.5 mL) are charged to the reaction vessel. The
reaction is heated to 35° C., then pressurized with carbon dioxide
(300 psi) and stirred. After 6 h the reaction is vented and quenched with
acidic methanol (5 mL). The reaction is cooled to room temperature, and
the resulting polymer is diluted with acetone (50 mL) and transferred to
a pan. The unreacted propylene oxide and acetone are removed by
evaporation to provide polymer 8a as a viscous oil.

[0295] A 100 mL reactor is charged with polymer 8a (10 g) and zinc
hexacyanocobaltate catalyst (0.02 g). The mixture is stirred and heated
to 105° C., and is stripped under vacuum to remove traces of water
from polymer 8a. Ethylene oxide (2-3 g) is added in one portion. The
reactor pressure is then monitored carefully. Additional ethylene oxide
is not added until an accelerated pressure drop occurs in the reactor
indicating that the catalyst has become activated. When catalyst
activation is verified, the remaining ethylene oxide (20 g) is added
gradually to keep the reactor pressure at about 10 psig. After ethylene
oxide addition is complete, the mixture is held at 105° C. until a
constant pressure is observed. Residual unreacted monomer is then
stripped under vacuum from the product, and the residue is cooled and
recovered to provide polymer 8 as a viscous oil.

[0298] In a glovebox, catalyst C-I (5.4 mg) and PPN-chloride (4.8 mg) are
charged to an oven-dried 20 mL glass liner. The liner is inserted into a
stainless steel high pressure reactor. The system is purged with N2
five times and purged with CO2 twice. While under the positive flow
of CO2, propylene oxide (5 mL) and propylene glycol (200 μL) are
charged to the reaction vessel. The reaction is heated to 35° C.,
then pressurized with carbon dioxide (300 psi) and stirred. After 6 h the
reaction is vented and quenched with acidic methanol (0.2 mL). The
reaction is cooled to room temperature, and the resulting polymer is
diluted with acetone (5 mL) and transferred to a foil pan. The unreacted
propylene oxide and acetone are removed by evaporation to produce polymer
9a as a viscous oil.

[0299] In a dry flask, 1 g of polymer 9a and 5 mg of zinc
hexacyanocobaltate catalyst are combined. To this mixture is added 2 g of
ethylene oxide. This mixture is stirred at rt for 48 h, then heated to
105° C. for 1 h. Residual unreacted monomer is then stripped under
vacuum from the product, and the residue is cooled and recovered to
provide polymer 9 as a viscous oil.

[0300] Supercritical Carbon Dioxide Solubility Tests:

[0301] Samples were evaluated for supercritical CO2 (sc-CO2)
solubility at a range of pressures and concentrations using the apparatus
and conditions described in the Journal of Supercritical Fluids 34
(2005), pp. 11-16, and Journal of Physical Chemistry 100 (1996) which are
incorporated herein by reference.

[0302] The solubility of the polymers of Examples 1-3 and related
compounds in supercritical CO2 and various concentrations,
temperatures, and pressures are shown in FIGS. 1-4.

[0303] Emulsion Tests:

[0304] Samples were evaluated for the ability to stabilize foams between
supercritical CO2 (sc-CO2) and water. Foam test conditions used
a windowed cell containing equal volumes of liquid sc-CO2 and brine
or water. The mixtures were agitated in the presence of 0.1 wt %
surfactant (based on mass of CO2) and the stability of the foam was
observed visually by periodically measuring the height of foam present in
the CO2 phase and the depth of foam present in the aqueous phase.
Plots of these data for the polymer compositions of examples 1-3 and
related materials are shown in FIGS. 4 and 5.

[0305] Further detail on suitable experimental conditions for these
measurements are found in Fluid Phase Equilibria (2003), 211(2), pp
211-217 and in Chemistry of Materials (2002), 14(10), pp 4273-4280 which
are both incorporated herein by reference.

Other Embodiments

[0306] The foregoing has been a description of certain non-limiting
embodiments of the invention. Accordingly, it is to be understood that
the embodiments of the invention herein described are merely illustrative
of the application of the principles of the invention. Reference herein
to details of the illustrated embodiments is not intended to limit the
scope of the claims, which themselves recite those features regarded as
essential to the invention.